Metrix 5550 Instruction Manual

5550 & 5550G MECHANICAL VIBRATION SWITCHES
User Guide / Installaon Manual
DOC# 1231558 • REV C (November 2017)
1180
1180
MODEL 5550
MODEL 5550G
The 5550 and 5550G mechanical vibraon
switches provide vibraon protecon for
low- to medium-speed machinery. An inera
sensive mechanism acvates a snap-acon
switch with SPDT output contacts if the vi-
braon exceeds an adjustable setpoint. The
5550 mechanical vibraon switch contacts
can be used to acvate an alarm or iniate
equipment shutdown. The housing is weath-
erproof with an oponal hazardous area
rang. Electrical (remote) reset with start-up
me delay and a second set of SPDT output
contacts to accommodate DPDT needs
(e.g. separate trip and trip light circuits) are
available.
The 5550G uses idencal internal mecha-
nisms, but carries an IECEX rang ideal for
IIC gas group applicaons.

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1. PRINCIPLES OF OPERATION
1.1 Overview
Model 5550 and 5550G Mechanical Vibraon Switches oer basic protecon against gross
changes in structural seismic acceleraon. The two units are idencal internally and dier
only in their enclosure style and external access to adjustments. The 5550G is used for haz-
ardous area applicaons requiring gas group IIC approvals, but has no externally accessible
adjustments. The 5550 has externally available setpoint adjustment and reset facilies, and
can be used for applicaons up to gas group IIB + hydrogen. Refer to hazardous area instal-
laon manuals M8905 (model 5550) and 100356 (model 5550G) for addional informaon.
The operang mechanism is purely mechanical and
consists of a tension spring aached to a pivong
plate on an over-center fulcrum – magnets are not
employed. Normally, this plate is in an untripped
posion (Figure 1A). However, in the presence of
sucient seismic acceleraon (whether vibratory
or impact), the trip plate will pivot beyond this
over-center posion, snapping to a stable tripped
posion (Figure 1B) where it contacts an internal
micro-switch relay, changing the state of the relay.
This relay is available for external wiring connec-
ons where on/o changes in electrical connuity
can be used to trip the machine and/or annunci-
ate excessive vibraon.
Once the switch has assumed its tripped posion,
it must be reset manually by means of the external
reset plunger (5550 only), or by means of a remote
electrical reset (standard on 5550G, oponal on
5550). The remote reset capability can also be
used as a startup delay to hold the switch in an
untripped state for as long as coil excitaon is sup-
plied – up to 30 seconds (the maximum duraon
is governed by a non-adjustable, factory-installed
thermistor circuit). The startup delay feature is useful during machinery startup when vibra-
on in excess of the normal trip seng may be temporarily incurred.
1.2 Typical Applicaon
The model 5550 and 5550G mechanical vibraon switches are typically used on cooling
tower fans and mounted such that loss of a blade will result in signicant structural accelera-
on at the switch mounng locaon (Figure 2).
The switch may be used on other types of machin-
ery as well, but care must be taken to ensure that
adequate change in acceleraon between “normal”
and “malfuncon” condions will exist at the switch’s
mounng locaon. The switch is not designed to reli-
ably trip for acceleraon levels below approximately
1 g (9.8 m/s2), or when less than 1 g exists between
a machine’s normal running vibraon levels and mal-
funcon vibraon levels. Figure 2: Typical 5550 installaon on
cooling tower fan support strut.
Figure 1A: 5550 mechanical switch trip
mechanism in untripped posion. Micro-
switch (red) is not actuated.
Figure 1B: 5550 mechanical switch trip
mechanism in tripped posion. Micro-
switch (red) is actuated.

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1.3 Primary Variables Aecng 5550 Operaon
The required seismic acceleraon to move the 5550 or 5550G mechanical switch from its un-
tripped posion to its tripped posion is a funcon of three variables as detailed in secons
1.3.1 through 1.3.4.
1.3.1 Variable #1 – Spring Force Direcon
The movable trip plate mass inside the switch housing is
free to move on an essenally friconless pivot, and is
restrained in its untripped posion by a spring. By turning
the setpoint adjustment screw (Figure 3), changes are made
to the spring’s direcon, and to a much lesser extent, its
tension. Thus, the spring mechanism exerts an essenally
constant force on the trip plate and turning the setpoint ad-
justment screw changes the direcon of this force. Turning
the setpoint screw clockwise (CW) aligns the spring force
more fully in the untripped direcon (below the pivot – see
Figure 1), making it more dicult to trip the device. Turn-
ing the setpoint screw counter-clockwise (CCW) does the
opposite, making it easier to trip the device.
SETPOINT
ADJUST
RESET PLUNGER
FIGURE 3: MODEL 5550 setpoint
adjustment and manual reset.
NOTE: Metrix Mechanical Vibraon Switches
are not intended for use on high-speed tur-
bomachinery or on machines where changes in
seismic acceleraon smaller than 1G must be
reliably detected. Instead, Metrix oers more
sophiscated electronic vibraon sensing soluons that
are beer suited for such applicaons.
NOTES:
1. Turning the screw too far in the counter clockwise (CCW) direcon will eventu-
ally pull the spring past the over-center locaon and cause the switch to snap
into the tripped posion without any external ineral excitaon. When adjusted
in this manner, the switch cannot be reset from its tripped posion. Also, the
nature of this over-center mechanism can cause it to be very unstable when adjusted too
close to its equilibrium locaon, resulng in false trips.
2. The setpoint adjustment screw on the model 5550G switch is not externally accessible.
The cover must be removed. Do not remove the cover while energized circuits are pres-
ent in hazardous areas
1.3.2 Variable #2 – Switch Orientaon
Depending on how the switch is oriented, gravity will act on the trip mechanism’s mov-
able mass to either add to or subtract from the spring force. For both model 5550 and
5550G switches, the switch orientaon is the direcon in which the cover faces. With the
switch oriented horizontally (Figure 4A), the eects of gravity will be negligible and only

Doc# 1231558 • REV C (November 2017) Page 4 of 20
FIGURE 4: Side views showing horizontal and vercal orientaons of 5550 switch
NOTE: Depending on how the setpoint is adjusted, sim-
ply turning the switch on its side or upside down may be
sucient to cause it to trip, due to the eects of gravity.
1.3.3 Variable #3 – Vibraon Forces Acng on the Switch
By shaking or impacng the switch along its sensive axis with sucient ineral force for
a sucient duraon and within its frequency response range, the trip plate mechanism
will overcome the combined forces of gravity (depending on orientaon) and spring ten-
sion, snapping from its untripped posion to its tripped posion.
2. INSTALLATION
the spring force will govern the trip plate’s behavior. With the switch oriented vercally
up (Figure 4B), gravity acts to keep the trip plate’s movable mass in the untripped posion,
and ineral excitaon must counteract both gravity and the spring force. With the switch
oriented vercally down (Figure 4C), gravity acts in the opposite direcon and opposes the
spring’s force. Thus, with the same setpoint adjustment, a switch facing up will require the
most excitaon to trip, a switch facing horizontally will require 1g less excitaon to trip, and
a switch facing down will require 2g less excitaon to trip.
WARNING: Before proceeding to wire and install model 5550 and 5550G switch-
es, read and thoroughly understand these instrucons. They are intended for
experienced personnel who require only basic installaon guidance, and assume
that the switch has already been selected and applied properly for the machinery at hand.
When installing the switches in hazardous atmospheres, refer to Metrix manuals M8905
(5550) and 100356 (5550G) for important safety informaon. All of these manuals, as
well as addional technical resources, are available on our website at www.metrixvibra-
on.com. You may also contact Metrix or its local representave for addional assistance,
using the informaon on the last page of this manual.
GRAVITY
SENSITIVE
AXIS
GRAVITY
SENSITIVE
AXIS
GRAVITY
SENSITIVE
AXIS
4A: Horizontal orientaon,
cover facing right
4B: Vercal orientaon,
cover facing up
4C: Vercal orientaon,
cover facing down

Doc# 1231558 • REV C (November 2017) Page 5 of 20
NOTE: When specifying units with 2g reset coil holding
strength simultaneously with a 24 VDC reset coil, do not install
the switch with a horizontal orientaon or upside down. The
reset coil lacks sucient holding force for anything other than
a vercal “face up” orientaon (Figure 4B).
2.1 Maintenance Convenience Versus Measurement Quality
While it is desirable to mount the switch in a locaon in which it can be easily serviced and
maintained, this should not be the dominant consideraon. The switch serves as a me-
chanical sensor and for it to provide suitable machinery protecon, it must be mounted in a
locaon and orientaon where the machine’s ineral forces during malfuncon condions
will be suitably large to trip the switch. Thus, locang the switch for opmal mechanical
sensing – rather than opmal serviceability – must always remain the primary consideraon.
However, in most circumstances, judicious choice of mounng locaon and switch orienta-
on can accommodate both requirements sasfactorily.
2.2 Sensive Axis
The switch is designed to respond to ineral forces only in the direcon of its sensive axis
(Figure 4). When care is not taken to mount the switch properly, relavely large ineral
forces can occur elsewhere on the machine that will not be transmied properly to the
switch, and/or will occur in a direcon perpendicular to the switch’s sensive axis. Both of
these condions can render the switch’s ability to trip less eecve or even ineecve.
2.3 Horizontal Orientaon
A horizontal orientaon of the switch means that it is mounted with its sensive axis per-
pendicular to the direcon of gravity (refer to Figure 4A). In this orientaon, the eects of
gravity on the switch’s trip mechanism are negligible and the trip point is governed almost
enrely by the spring. It is recommended that the switch be oriented horizontally because
most machines are less constrained (less s) in the horizontal direcon than in the vercal
direcon and will therefore vibrate more in the horizontal direcon.
2.4 Vercal Orientaon
A vercal orientaon of the switch means that it is mounted with its sensive axis parallel to
the direcon of gravity. It is not recommended that the switch be oriented vercally (except
as noted above) because most machines are more constrained (more s) in the vercal di-
recon than in the horizontal direcon, and will therefore vibrate less in the vercal direcon.
2.5 Horizontal Machines
Although Figures 5 and 6 both show horizontal switch orientaons, they are not equivalent.
In Figure 5, the sensive axis of the switch points directly at the machine’s sha; in Figure
6, it does not and instead is aimed at point P somewhere above the sha. Either mounng
orientaon can be eecve, but 5 is preferred.

Doc# 1231558 • REV C (November 2017) Page 6 of 20
SHAFT CENTERLINE
CONDUIT
5550 MOUNTING LOCATION
WITH CONDUIT FITTING
FACING DOWN
BASEPLATE
SHAFT Z AXIS
(AXIAL)
CONDUIT
END VIEW
SIDE VIEW
NOTE: A drain hole at low point is
recommended to allow accumulated
moisture to exit (except in
explosion-proof installations)
Shaft Radial YAxis
Shaft Radial XAxis
SHAFT CENTERLINE
SHAFT CENTERLINE
CONDUIT
5550 MOUNTING LOCATION
WITH CONDUIT FITTING
FACING DOWN
BASEPLATE
SHAFT Z AXIS
(AXIAL)
CONDUIT
END VIEW
SIDE VIEW
NOTE: A drain hole at low point is
recommended to allow accumulated
moisture to exit (except in
explosion-proof installations) SHAFT CENTERLINE
P
Shaft Radial YAxis
Shaft Radial XAxis
Figure 5: Horizontal machine showing horizontal 5550 mounng orientaon and preferred locaon.
Conduit ng faces down to allow drainage of any condensaon.
Figure 6: Horizontal machine showing horizontal 5550 mounng orientaon and alternate locaon.
Conduit ng faces down to allow drainage of any condensaon.
Figure 7 shows the same horizontal machine as in Figures 5 and 6, but with the switch ori-
ented vercally. As noted in Secon 2.4, a vercal orientaon of the switch is discouraged
because machines will generally experience less vibraon in the vercal direcon than in
the horizontal direcon, and the switch will be less eecve. Metrix does not recommend
installaon as shown in Figure 7 unless the machine truly experiences more vibraon in the
vercal direcon than in the horizontal direcon, or the 2g / 24V reset coil opon is being
used (see note in Secon 2.4).

Doc# 1231558 • REV C (November 2017) Page 7 of 20
Figure 7: Horizontal machine showing verctal 5550 mounng orientaon (not recommended).
SHAFT CENTERLINE
5550 MOUNTING LOCATION
BASEPLATE
SHAFT Z AXIS
(AXIAL)
CONDUIT
END VIEW
SIDE VIEW
Shaft Radial YAxis
Shaft Radial XAxis
SHAFT CENTERLINE
2.6 Vercal Machines
Figure 8 shows the preferred installaon for a vercal machine. The switch is mounted
horizontally and with its sensive axis poinng directly at the sha.
In contrast, Figure 7 shows the switch mounted vercally, which is not recommended.
Because most vercal machines (like horizontal machines) are rigidly xed by a baseplate
or other mounng that constrains them from vibrang in the vercal direcon, aligning the
switch’s sensive axis in the vercal direcon aligns it in the direcon of least vibraon.
Instead, mount the switch as shown in Figure 5 to ensure that radial (not axial) vibraon is
detected. Mount the switch as shown in Figure 7 only when the machine actually vibrates
more in the vercal than horizontal direcon, or when the 2 g /24 V reset coil opon is used
(see note in secon 2.4).
SHAFT CENTERLINE
CONDUIT
BASEPLATE
5550 MOUNTING LOCATION
WITH CONDUIT FITTING
FACING DOWN
BASEPLATE
SHAFT Z AXIS
(AXIAL)
CONDUIT
TOP VIEW
SIDE VIEW
NOTE: A drain hole at low point is
recommended to allow accumulated
moisture to exit (except in
explosion-proof installations)
Shaft Radial YAxis
Shaft Radial XAxis
Figure 8: Vercal Machine showing horizontal 5550 mounng orientaon and recommended locaon

Doc# 1231558 • REV C (November 2017) Page 8 of 20
2.7 Mounng Rotaon
The switch can be rotated about its sensive axis without aecng its operaon (Figure 9).
Thus, posions 9A, 9B, 9C, and 9D showing the model 5550 switch rotated at 12:00, 3:00,
6:00, and 9:00 posions respecvely do not aect the operaon of the switch and are pri-
marily a maer of preference and serviceability. However, when possible, it is recommend-
ed that conduit ngs be oriented facing down, helping to prevent moisture or condensa-
on accumulaon inside the device.
2.8 Axing The Switch To The Machine
Mount the switch securely to the machine using the 4-hole paern (5550) or 2-hole paern
(5550G) on the baseplate. It is extremely important that the device be rigidly aached
to the machine so that it reects machinery vibraon – not vibraon incurred by a loose
mounng, an insuciently s mounng bracket, or a bracket resonance. Also, the switch
should be mounted in a locaon where its own mass does not appreciably aect the natural
frequency(ies) of the member to which it is aached. When aaching to a support beam,
skid, or other member, thought should be given to the usefulness of the measurement and
what level of machinery damage must be present before sucient acceleraon will occur at
the measurement locaon. For addional applicaon assistance, consult the factory or your
nearest Metrix representave.
2.9 Wiring
The switch provides a single SPDT relay or oponal double SPDT relays, allowing use as a
DPDT device. When a reset / startup delay coil is specied (oponal on 5550; standard on
5550G), suitable wiring terminals are also available. Refer to Figure 10 for wiring terminal
assignments.
9A - 12:00 horizontal orientaon
9B - 3:00 horizontal orientaon
9C - 6:00 horizontal orientaon
9D - 9:00 horizontal orientaon (preferred)
Figure 9: Horizontal orientaons of 5550. 9D posion is strongly recommended
(conduit hole facing down) to allow drainage oof any accumulated condensaon.
GRAVITY

Doc# 1231558 • REV C (November 2017) Page 9 of 20
When wiring the device, observe the following:
2.9.1 Do not exceed switch contact rangs listed on the nameplate.
2.9.2 Comply with all applicable electrical codes.
2.9.3 Keep eld wiring away from the moving parts of the trip plate mechanism.
2.9.4 All power must be switched o before opening the enclosure in an explosive
atmosphere.
2.9.5 The switch must be electrically connected by means of a ameproof/dust cable
gland or stopping box cered to IEC60079-0:2011 (EN60079-0:2012), IEC60079-1:2007
(EN60079-1:2007), and IEC600079-31:2008 (EN60079-31:2009).
2.9.6 For ambient temperatures below -10°C, use eld
wiring suitable for the minimum ambient temperature.
2.9.7 Reinstall the cover by rst ensuring the o-ring
is in place and properly seated in the housing’s groove.
Place the cover on the unit and screw ght (model
5550G) or by torqueing the four cover bolts shown in
Figure 11 (model 5550 only) to 6-7 /lbs.
NOTE: It is not recommended
that wiring be connected to the
device unl aer verifying the
factory default setpoint in Secon
4.1 and performing the in-situ setpoint
adjustments in Secon 4.2. This will pre-
vent having to disconnect the wiring and
remove the device from its mounng loca-
on. It will also prevent unwanted trips
while inially adjusng the setpoint.
WARNING: Voltages present at
switch terminals can result in
serious injury or death. Always
de-energize these circuits prior
to installaon or maintenance and use
appropriate lock-out / tag-out proce-
dures where applicable.
CAUTION: If eld wiring is allowed to obstruct the
moving parts of the switch, it may prevent the trip
plate from operang correctly. Machinery protec-
on can be compromised and serious machinery damage
and/or personnel injury may result.
NOM
OPEN
COM
NOM
CLOSED
RESET COIL
CASE
RESET COIL
L(+)
N(-)
GRN
NOM
OPEN
COM
NOM
CLOSED
RESET COIL
CASE
RESET COIL
L(+)
N(-)
GRN
NOM
OPEN
COM
NOM
CLOSED
WIRING DIAGRAM
SPDT DPDT
DPDT CONTACTS AND RESET COIL OPTION
Figure 10: Wiring connecons
Figure 11: 5550 cover bolts locaon
2
1
3
4

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2.10 Conduit: When aaching conduit, observe the following:
2.10.1 Avoid long runs of unsupported conduit that can transfer unwanted impacts or
vibraon of the conduit, rather than of the machine.
2.10.2 Always slope conduit away from the switch and generally orient such that accumu-
lated moisture or condensaon does not drain into the switch. For non-explosion proof
installaons, consider the use of an adequate number of J-traps or other drain mecha-
nisms at low points to preclude moisture from collecng in the switch or in the conduit.
When possible, mount the switch so that the conduit outlet faces down.
2.10.3 Units with NPT conduit holes (ordering opon E=1, 2, 3, 7) have ¾” NPT threads.
Units with metric conduit holes (ordering opon E=4, 6, and 8) have M20 x 1.5 threads.
Refer to Metrix datasheet # 1004461 for a complete list of ordering opons.
2.10.4 Use proper conduit seals and hole plugs meeng the environmental requirements
of the installaon to prevent ingress of moisture and dust.
2.11 Protecng Against Moisture Ingression
All installaons should observe the guidelines of 2.10. These are parcularly important
when the switch will be mounted in moist environments such as on cooling tower struc-
tures, evaporave fans, marine applicaons, or other installaons where the switch will be
exposed to rain, elevated humidity, hose-directed water, or any environmental condions
that might allow condensaon to form at or in the switch, associated wiring, and conduit.
2.11.1 Ensure the cover is properly ghtened
The importance or properly ghtening cover bolts (5550) or screw-type lid (5550G) per-
tains not just to sealing against ignion of a ammable atmosphere outside the switch,
but also to prevent dust or moisture ingression to the switch internals.
2.11.2 Examine Cable Insulaon for Nicks and Cuts
In some cases, properly rated cable may be installed without solid or exible conduit to
NOTE: The disposable plasc plugs that ship in each con-
duit hole provide only physical thread protecon during
shipping and handling. They are not designed for use as
permanent hole plugs and do not provide adequate environ-
mental protecon for the switch when installed in the eld.
CAUTION: Do not over-torque or under-torque
housing screws. Over torqueing can damage the
housing and compromise the seal. Under torque-
ing can permit moisture to weep into the switch. Either
condion can compromise switch operaon and/or present
an electrical shock hazard.
NOTE: Do not over-torque the cover bolts on the model 5550
switch. This could damage the housing and compromise the seal.

Doc# 1231558 • REV C (November 2017) Page 11 of 20
preclude it as a potenal source of moisture collecon. However, whether installed with
or without conduit, all cables should be examined for nicks and cuts that compromise the
protecve outer jackeng. In parcular, mul-conductor cables can act as very eecve
wicks when the outer jacket has been cut or damaged. Once moisture ingresses into the
cable, it will oen nd its way into the switch via this wicking mechanism, even when an
appropriate gland seal is used at the switch’s conduit opening and the outer periphery of
the cable is not leaking at the gland.
2.11.3 Liberally Apply Silicone Dielectric Grease to all Openings
The primary points of moisture entry into the switch are where the housing is penetrated:
- The setpoint adjustment screw (5550 only)
- The reset plunger (5550 only)
- The conduit ng(s)
- The seal between housing body and housing cover
O-ring seals and gaskets are used at each of these entry points and silicone dielectric
grease is applied at the factory. However, in extremely moist environments an addional
liberal coang of silicone dielectric grease should be applied in the eld at me of
installaon. This pracce will provide added protecon against moisture ingression
over me. Metrix recommends Dow Corning #33 Molykote® Extreme Low Temperature
Silicone Grease or equivalent.
2.12 Outline Diagrams and Physical Dimensions
Refer to the Metrix product datasheet # 1004461, available at www.metrixvibraon.com
3. IMPORTANT SAFETY INFORMATION
3.1 General Safety Summary
Review the following safety precauons to avoid injury and prevent damage to this product
or any products connected to it.
• USE ONLY AS SPECIFIED
To avoid potenal hazards, use this product only as specied. Only qualied personnel
should perform installaon and removal procedures.
• CONNECT AND DISCONNECT PROPERLY
Do not connect or disconnect this product while it is connected to a live power source.
• GROUND THE PRODUCT
The housing of this product should be connected to earth ground. Before energizing the
product, ensure its housing is properly grounded.
• OBSERVE ALL TERMINAL RATINGS
To avoid re or shock hazard, observe all rangs and markings on the product. Consult
the individual secons of this manual for further informaon before making connecons
to the product.
• DO NOT OPERATE WITHOUT COVER
The cover serves mulple purposes that may include protecon against moisture and
dust ingression, protecon of personnel from electrical shock, and protecon against

Doc# 1231558 • REV C (November 2017) Page 12 of 20
ignion of ammable atmospheres when used in locaons with hazardous area rangs.
Do not use the device without its cover except when making adjustments or connecons
as noted in this manual.
• AVOID EXPOSURE TO CIRCUITRY
Do not touch exposed electrical connecons and components when power is present.
• DO NOT OPERATE WITH SUSPECT FAILURES
If you suspect there is damage to this product, have it inspected by qualied personnel.
3.2 Safety Terms and Symbols
Terms that appear in this manual requiring special aenon include:
• WARNING: Warning statements idenfy condions or pracces that could result in
injury or loss of life.
• CAUTION: Cauon statements idenfy condions or pracces that could result in
damage to the product, loss or corrupon of data, or damage to the environment or
other property.
• NOTE: Notes idenfy material of special interest or importance to the user, not includ-
ing cauons or warnings.
Symbols that may appear on the product and/or in this manual include:
• HIGH VOLTAGE PRESENT
• DANGER or CAUTION
4. SETPOINT ADJUSTMENT
Metrix mechanical vibraon switches are shipped from the factory such that when slowly
rotated 180 degrees from an upright posion (cover facing up) to an upside down posion
(cover facing down), the trip plate will snap from its untripped posion to its tripped posi-
on.
4.1 Vericaon of Factory Setpoint
To verify the factory setpoint, place the switch on a at surface with the cover facing up.
Do not connect any wiring yet. Press the reset plunger (model 5550 only – remove cover
on model 5550G) to ensure the switch is in its untripped posion (it may have tripped due
to shock or vibraon incurred during shipping and handling). Then, slowly li the switch
• PROTECTIVE EARTH
• FUNCTIONAL GROUND
• NOTE

Doc# 1231558 • REV C (November 2017) Page 13 of 20
CAUTION: The default setpoint as shipped from the factory is
not intended to be suitable for any parcular machinery appli-
caon. Each applicaon requires that the setpoint be careful-
ly eld adjusted for the specics of your machine as outlined in Secon
4.2 below. Failure to adjust the setpoint in this manner constutes a
misuse of the product and may lead to ineecve machinery protecon
resulng in extensive machinery damage and personnel injury.
up and rotate it to an upside down posion as shown in Figure 12. As the switch reaches
the 180-degree posion, you should hear an audible “click” indicang it has snapped to its
tripped state. If the device does not trip, turn the setpoint adjustment screw approximately
1/16th turn CCW and repeat the above procedure. Connue adjusng in 1/16th CCW turn
increments unl the unit trips when turned from right side up to upside down. When per-
forming this vericaon on the Model 5550G, it is recommended that you leave the cover
o. The presence or absence of the cover does not aect the setpoint during the vericaon
process and ensures the cover does not have to be repeatedly removed and reinstalled to
adjust the setpoint and reset the trip plate. However, never remove the cover with ener-
gized wiring connected – remove power before opening cover.
NOTE: If the switch will not
reset, adjust the setpoint screw
1/8th turn CW and press the
reset buon. Repeat this pro-
cedure, adjusng 1/8th of a turn each
me, unl the device can be reset.
While performing this procedure,
keep the device sing on a at sur-
face with the cover side facing up.
4.2 In-Situ Setpoint Adjustment
The setpoint adjustment is accessible externally on the model 5550 (see Figure 3). For model
5550G, the lid must be removed. Follow the steps below to adjust the setpoint for the par-
culars of your machine.
4.2.1 Verify the factory setpoint as described in 4.1 above. Then, rotate the adjustment
screw one full turn (360 degrees) clockwise and proceed to step 4.2.2.
4.2.2 Install the switch on the machine following the guidelines of secon 3. Ensure
the eld wiring is disconnected. If it has already been connected, disconnect temporarily,
Figure 12: Verifying the factory default
setpoint on the 5550

Doc# 1231558 • REV C (November 2017) Page 14 of 20
NOTE: The objecve is to establish a setpoint as close as possible to
normal operang condions, while sll allowing normal uctuaons
in speed, load, ow, etc. without false trips. Establishing a setpoint
that is too high may render machinery protecon ineecve. DO NOT at
this me aempt to adjust the setpoint for high vibraon encountered
during machine startup. This will be addressed in step 4.2.11.
taking appropriate cauons around any wiring that is (or may become) energized during
machine starng sequences and the setpoint adjustment procedure.
4.2.3 Reset the switch by depressing the reset plunger (5550) or manually pushing the
exposed trip plate into its untripped posion (5550G).
4.2.4 Connect a connuity tester or ohmmeter across COM & NOM OPEN terminals
(refer to Figure 10). This will allow you to visually conrm when the normally open relay
contacts close, indicang the switch has tripped. This is also true for COM & NOM CLOSE,
the normally closed relays contacts open when tripped.
4.2.5 Hold the reset plunger (5550) or trip plate (5550G) down and start the machine.
When the machine has reached running speed, release the plunger (5550) or trip plate
(5550G).
4.2.6 If the switch trips when releasing the plunger/trip plate, rotate the setpoint screw
a full turn (360 degrees) CW and then depress the plunger/trip plate, holding it in the
untripped posion. Release the plunger/trip plate once again and watch to see if the
switch trips. Repeat this process unl the switch does not trip with the machine running
at normal operang speed. Then, proceed to step 4.2.7.
4.2.7 With the machine running, SLOWLY turn the setpoint adjustment screw CCW unl
the switch trips. Then, turn the screw in the opposite direcon (CW) 1/8th turn, or ac-
cording to OEM instrucons, and reset the switch.
4.2.8 Allow the machine to run for as long as necessary to ensure the switch does not
trip under normal speed, load, and other operang condion changes. If the switch does
not trip, proceed to step 4.2.10. If it trips, proceed to step 4.2.9.
4.2.9 (Perform this step only if the switch tripped in step 4.2.8.) Turn the setpoint
adjustment screw in the CW direcon (increasing setpoint) in the smallest increment pos-
sible – preferably 1/16th turn or less, or according to OEM instrucons. Reset the switch
and repeat step 4.2.8.
NOTE: This step accomplishes two objecves. First, it allows the in-
staller to easily ascertain when the switch has snapped from its un-
tripped state to its tripped state, as it may be dicult or impossible
to listen for an audible “click” in the presence of ambient machine noise.
Second, it allows appropriate setpoint adjustments to be made without
unnecessary trips of the machine (repeated starts/stops on a machine are
usually undesirable and may be electrically and/or mechanically damaging
in some circumstances).

Doc# 1231558 • REV C (November 2017) Page 15 of 20
4.2.10
4.2.11 You have now established your unique setpoint and no further adjustment is
required. If the switch was supplied with an oponal reset / startup delay coil, connect all
eld wiring and proceed to secon 5. If the switch was not supplied with this coil, proceed
to step 4.2.11 to determine whether a startup delay is needed for your applicaon.
4.2.12 Stop the machine, press the reset plunger pushbuon to ensure the switch is in its
untripped state, and then restart the machine. If the switch does not trip during machine
startup, you do not require a startup delay. Connect all eld wiring and place the switch
into service. If it does trip due to elevated vibraon levels during startup, you will require
an appropriate startup delay coil (see secon 5). Consult the factory or your nearest
Metrix representave for assistance.
5. ELECTRICAL RESET AND STARTUP DELAY
When a reset coil is specied (standard on 5550G, oponal on 5550 where ordering opon D
= 1, 2, 3, or 4), an electrical solenoid mechanism is installed that allows remote reset of the
switch when in its tripped posion, and iniaon of a startup delay when in its untripped
posion. To acvate these features, the rated voltage must be applied to the reset coil wir-
ing terminals (refer to Figure 10). The reset funcon requires only momentary applicaon of
voltage. The startup delay funcon requires connuous applicaon of voltage for the dura-
on of the factory pre-set me delay (approximately 20-30 seconds).
5.1 Electrical (Remote) Reset
This feature allows remote reset of the switch from its tripped posion. To acvate,
momentarily apply the rated voltage across the appropriate terminals (refer to Figure 10),
taking care to observe the polarity. The applicaon of this voltage will energize the solenoid
mechanism, extending its plunger and reseng the switch to its untripped posion. Once
the solenoid has reset the switch, voltage can be removed. The switch will remain in its
untripped posion unl sucient acceleraon trips it.
5.1.1 Connuous Bypass
It is not possible to connuously bypass the switch using the reset funcon. A connu-
ous voltage across the reset terminals will acvate the startup delay feature lasng
approximately 20-30 seconds, aer which the switch will return to normal operaon. If a
connuous bypass funcon is required, an isolaon switch should be installed in the same
NOTE: If more than one full turn of the setpoint screw is re-
quired to accommodate variaons in normal running condions
without false trips, the 5550 may not be an appropriate device
for your applicaon. Contact the factory for assistance.
CAUTION: The switch’s setpoint must be established relave
to normal machinery operaon, not startup vibraon levels.
DO NOT adjust the setpoint screw to increase the switch’s
trip point if the machine trips due to high vibraon during startup.
The startup delay feature (oponal on 5550 – standard on 5550G) is
specically designed to suppress the switch from tripping for a pre-set
interval during startup. Elevang the setpoint to accommodate start-
up vibraon levels can result in missed trips during genuine machinery
malfuncon condions, and constutes a misuse of the switch.

Doc# 1231558 • REV C (November 2017) Page 16 of 20
NOTE: The reset coil circuit contains a thermistor that allows the circuit to
also funcon as a startup delay when voltage is connuously applied (see
secon 5.2). If the thermistor is hot, current will not ow and the reset
funcon will not operate. A cool-down period may be required (see Secon
5.2.1). In many applicaons, voltage is connuously applied to the reset coil ter-
minals while the machine is running. In such situaons, the thermistor will sll be
hot immediately following a trip and it will not be possible to electrically reset the
switch unl the thermistor has cooled suciently. If necessary, the switch can be
manually reset (5550 only), using the plunger pushbuon to allow a “hot” restart.
Alternavely, it may be desirable to program the machine’s control system to ap-
ply voltage to the reset coil for only 30 -40 seconds during machine start up. This
pracce will ensure that the thermistor is more likely to be “cold” following a trip,
allowing an immediate remote reset.
circuit as the output relay(s), allowing the 5550/5550G to be removed from the machinery
shutdown loop.
5.2 Startup Delay
The startup delay feature is intended for use in machines that exhibit high vibraon during
startup. This feature maintains the switch in an untripped posion for a factory pre-set
delay period of approximately 30 seconds, aer which the switch resumes normal operaon.
To acvate startup delay, connuously apply the specied voltage across the reset terminals
and the switch will be suppressed from tripping for the preset delay period, allowing the
machine to run up to operang speed and normal vibraon levels. Voltage must be connu-
ously applied for the duraon of the startup delay (approximately 30 seconds). If this volt-
age is removed prematurely, the coil will de-energize and the switch will not be suppressed
from tripping.
5.2.1 Thermistor Consideraons
The startup delay feature works through use of an internal thermistor in series with a sole-
noid mechanism. When voltage is connuously applied, current ows in the circuit and the
thermistor’s temperature rises, gradually restricng current ow. When the current drops
below the minimum value required to keep the coil energized, the solenoid retracts. Nor-
mally, it takes approximately 30 seconds for the thermistor to reach this “cut-o” tempera-
ture. However, several factors can serve to shorten or lengthen this interval as follows:
• Ambient Temperature Eects
The me for the thermistor to reach its cut-o value depends on the inial temper-
ature of the thermistor. If the switch is at an ambient temperature of -30C during
the winter months, it will obviously exhibit a longer startup delay than during the
summer months when ambient temperatures may be 30C. Likewise, if the switch is
placed on a machine that can sustain a large temperature rise at the mounng loca-
on, the switch may be near its maximum temperature rang of 70C aer a period
of prolonged operaon. This will shorten the startup delay interval when compared
to operaon on a “cold” machine.
WARNING: Voltages present at reset terminals can result
in serious injury or death. Always de-energize these
circuits prior to installaon or maintenance and use ap-
propriate lock-out / tag-out procedures where applicable.

Doc# 1231558 • REV C (November 2017) Page 17 of 20
• Cool-Down Period
If the circuit acvang the startup delay leaves the voltage connuously applied (as
is typical), the thermistor will remain hot unl voltage is removed, such as follow-
ing a machine trip. Thus, when the thermistor is not allowed to cool to its ambient
surroundings, it will shorten the startup delay.
• Immediate Restart
If a restart is required immediately following a trip, the thermistor may be so hot
that the switch cannot be immediately reset using the remote reset funcon. In
such situaons, it will be necessary to either manually reset the switch or wait for
the thermistor to cool suciently. Alternavely, it may be desirable to modify the
machinery control logic such that voltage is only applied to the reset terminals for
the duraon of the factory pre-set delay, ensuring that the thermistor circuit is only
energized at startup.
• Current Flow
The amount of current owing through the thermistor will be a funcon of the volt-
age applied, the thermistor’s resistance, and the resistance elsewhere in the circuit.
Loose, intermient, or corroded wiring connecons can increase resistance and result
in a longer startup delay interval. If the resistance is too great, the reset coil will not
energize at all due to insucient current. Insucient voltage and/or current can also
be a problem. Be certain that the coil voltage rang (ordering opon D) matches the
voltage and current your circuit supplies. See Table 1 on the following page.
Opon D
(coil voltage)
Opon C
(coil holding
force)
Rated
Voltage
Min
Voltage
Max
Voltage
Min
Current
Max Power
Consumpon
None (D=0) All N/A N/A N/A N/A N/A
115 Vac (D=1) All 115 Vac 103.5 Vac 126.5 Vac 1.24 A 287.5 W
230 Vac (D=2) All 230 Vac 207 Vac 253 Vac 0.32 A 230 W
24 Vdc (D=3) 5 g (C=1) 24 Vdc 22.8 Vdc 25.3 Vdc 1.58 A 60 W
2 g (C=2) 24 Vdc 22.8 Vdc 25.3 Vdc 1.18 A 28.8 W
10 g (C=3) 24 Vdc 22.8 Vdc 25.3 Vdc 2.88 A 72 W
115 Vdc (D=4) All 115 Vdc 103.5 Vdc 126.5 Vdc 1.20 A 207 W
Table 1: Reset / Startup Delay Coil Electrical Characteriscs
5.3 Coil Consideraons
5.3.1 Coil Hold Strength
The reset / startup delay coil is sized to provide a specied holding strength (opon C), al-
lowing the startup delay feature to hold the switch in its untripped state even in the pres-
ence of high vibraon encountered during machine startup. If the reset coil supplied will
not hold the switch in an untripped state during startup, it may be the wrong size. Refer
to Table 1 and consult the factory for assistance.

Doc# 1231558 • REV C (November 2017) Page 18 of 20
NOTE: The 24 VDC reset coil comes in three dierent versions,
depending on the holding strength opon specied (opon C).
Although each has the same min/max voltage rang, the current
draw will be larger for larger holding coil strengths, as noted in Table 1. Be
certain your power source for this coil is capable of supplying the neces-
sary current for the rated holding strength.
5.3.2 Duraon Consideraons
The duraon of the startup delay (approximately 30 seconds) is factory set and cannot
be altered. With the switch in an untripped state, connuous applicaon of the specied
voltage to the reset terminals will iniate the delay feature, but will not cause it to persist.
That is, applying a connuous voltage across the reset terminals for longer than 20-30
seconds does not allow one to arbitrarily increase the duraon of the startup delay. See
secon 5.2.1 for a more in-depth explanaon of the circuit operaon.
6. DRAWINGS, SPECIFICATIONS, AND ORDERING INFORMATION
Unless otherwise noted, all gures and illustraons in this manual depict the model 5550
mechanical switch. The 5550G is idencal in terms of its internal mechanisms, but has a
dierent housing that is rated for use in the more stringent IIC gas group. For addional in-
formaon on models 5550 and 5550G, including outline diagrams, Metrix specicaons, and
ordering informaon, refer to Metrix product datasheet # 1004461. Refer also to hazardous
area installaon manuals M8905 (5550) and 100356 (5550G) as appropriate.

Doc# 1231558 • REV C (November 2017) Page 19 of 20
7. HAZARDOUS AREA APPROVALS
MODEL 5550
IECEx Approval
(World):
IEC Markings:
Ex d IIB + H2 T6 Gb
Ex tb IIIC T85°C Db Ta -40°C to
+70°C IP66
IECEx BAS10.0020
IEC Standards:
IEC60079-0:2011
IEC600079-1:2007
IEC600079-31:2008
CAUTION: TO REDUCE
RISK OF IGNITION OF
HAZARDOUS ATMO-
SPHERES, DISCONNECT
THE SUPPLY CIRCUIT
BEFORE OPENING. KEEP
ASSEMBLY TIGHTLY
CLOSED WHEN IN
OPERATION. CABLE
TEMPERATURE RISE 15K
- U S E S U I T A B L E C A B L E .
ATTENTION: AFIN
DE PREVENTIR
L-INFLAMMATION
D’ATMOSPHERES
DANGEREUSES COUPER
L’ALIMENTATION ELEC-
TRIQUE CIRCUIT AVANT
D’OUVRIR COFFRET
GARDER LE COUVERCLE
BIEN FERMETANT QUE
LES CIRCUITS SONT
SOUS TENSION. TEM-
PERATURE DE CABLE
MONTE 15K - UTILISEZ
CABLE APPROPRIE.
ATEX Approval
(Europe):
ATEX Markings:
II 2GD Ex d IIB + H2 T6 Gb
Ex tb IIIC T85°C Db Ta -40°C to
+70°C IP66
Baseefa 10ATEX0098
EN Standards:
EN60079-0:2012
EN60079-1:2007
EN60079-31:2009
UL Approval
(North
America):
UL Markings:
Models 5550-2XX-XXX or
5550-7XX-XXXZ:
Class I, Div 1, Groups B,C,D,Class
II, Div 1,
Groups E,F,G, Type 4 or 4X, IP66
Models 5550-1XX-XXX or
5550-6XX-XXX:
Class I, Div 1, Groups C,D,Class
II, Div 1,
Groups E,F,G, Type 4 or 4X, IP66
UL/CSA Standards:
UL 698
UL 508
CSA C22.2 No. 25
CSA C22.2 No. 30
CSA C22.2 No. 14
1180

Doc# 1231558 • REV C (November 2017) Page 20 of 20
This electronic equipment was manufactured according to high quality stan-
dards to ensure safe and reliable operaon when used as intended. Due to its
nature, this equipment may contain small quanes of substances known to be
hazardous to the environment or to human health if released into the environ-
ment. For this reason, Waste Electrical and Electronic Equipment (commonly
known as WEEE) should never be disposed of in the public waste stream. The
“Crossed-Out Waste Bin” label axed to this product is a reminder to dispose of this product
in accordance with local WEEE regulaons. If you have quesons about the disposal pro-
cess, please contact Metrix Customer Service.
ENVIRONMENTAL INFORMATION
info@metrixvibraon.com
www.metrixvibraon.com
8824 Fallbrook Dr. Houston, TX 77064, USA
Tel: [phone] • Fax: [phone]
Aer Hours (CST) Technical Assistance: 1.713.452.9703
MODEL 5550G
IECEx Approval
(World):
IEC Markings:
Ex d I IC T6 Gb
Ex tb IIIC T85°C Db Ta
-40°C to +70°C IP66
IECEx BAS10.0095X
IEC Standards:
IEC60079-0:2011
IEC600079-1:2007
IEC600079-31:2008
CAUTION: TO REDUCE RISK
OF IGNITION OF HAZARDOUS
ATMOSPHERES, DISCONNECT THE
SUPPLY CIRCUIT BEFORE OPENING.
KEEP ASSEMBLY TIGHTLY CLOSED
WHEN IN OPERATION. CABLE
TEMPERATURE RISE 15K - USE
S U I TA B L E C A B L E .
ATTENTION: AFIN DE PRE-
VENTIR L-INFLAMMATION
D’ATMOSPHERES DANGEREUSES
COUPER L’ALIMENTATION ELEC-
TRIQUE CIRCUIT AVANT D’OUVRIR
COFFRET GARDER LE COUVERCLE
BIEN FERMETANT QUE LES
CIRCUITS SONT SOUS TENSION.
TEMPERATURE DE CABLE MONTE
15K - UTILISEZ CABLE APPROPRIE.
ATEX Approval
(Europe):
ATEX Markings:
I I 2 G D E x d I I C T 6 G b
Ex tb IIIC T85°C Db Ta
-40°C to +70°C IP66
B a s e e f a 1 0 A T E X 0 1 7 7
EN Standards:
EN60079-0:2012
EN60079-1:2007
EN60079-31:2009
1180