SKF PHL FM 10/400 User manual

SKF Belt Frequency
Meter user manual
User manual box edition

General safety tips
Safety rst – read and understand this manual before
operating the SKF Belt Frequency Meter.
Never use your SKF Belt Frequency Meter on moving belts.
Switch on and isolate any
belt drive system prior to
taking tension measurements
or attempting any other
installation work.
Do not drop the meter or
subject either the meter or
the optical sensor to other
sharp impact.
Do not put water, solvents
(including cleaning solutions)
or any other liquid on the
unit. Clean meter and
sensor with dry cotton cloth.
Do not pull on sensor cord.
Disconnect sensor from
meter by grasping the
connector grip only.
Do not leave the unit in
places that are humid, hot,
dust lled or in direct
sunlight.
Hint: When SKF Belt
Frequency Meter is not used
for a while, remove batteries
and store unit in the case
provided.
Do not use your SKF Belt
Frequency Meter in any
potentially explosive
environment.
Do not disassemble or
attempt to modify either the
meter or the sensing head.

Table of contents
1.0 Device description 4
2.0 Quick start 5
3.0 Functions
3.1 Keys 6
3.2 Audio/ visual display 7
3.3 Optical sensor 8
3.4 Battery condition 9
3.5 Charging batteries 10
4.0 Setup & use 11
5.0 Operating tips 13
6.0 Meter range 14
7.0 Calibration
7.1 Spot check 15
7.2 Annual certication 16
8.0 Technical specication 17
9.0 Useful formulae and conversions 18
Appendix
1.0 Theory of operation 19
2.0 Limited warranty 20
3.0 Belt mass constants 21
page

4
1.0 Device description
The SKF Belt Frequency Meter is a two component system consisting of a hand-held meter
attached to an optical sensor via an electronic cable. The sensor uses an infrared beam to detect
the vibration of a belt strand and sends a signal to the meter. (The sensor includes an LED that
produces an orange light beam to help aim the invisible infrared ray.) Comparing this input to
the vibration of a quartz crystal, the meter computes the natural frequency of the belt. The result
is shown in the display window as hertz (oscillations per second). The internal programming of
the meter is also able to report the belt tension in units of force (either newton or pounds-force)
provided the operator has entered the belt mass and span length using the manually operated
key pad.
The meter operates on four “AA” batteries. Battery life is approximately 20 hours. The battery
compartment is accessible at the back of the meter. This manual, a tuning fork for checking
calibration and a storage case are included with the complete kit.
LED aiming
beam
Optical sensor
see section 3.3 Plug in
sensor cable
Display
window see
section 3.2
Keypad see
section 3.1

5
2.0 Quick start
1. Plug in sensor
2. Press
to switch
meter on
3. Aim sensor at belt, gap
5 to 25 mm
4. Tap or
pluck belt
5. Read belt
frequency (Hz)

6
3.0 Functions
3.1 Keys
ON/OFF
SPAN
(m)
MASS
(kg/m)
UP
(Hz/N)
DOWN
(Lbs)
MEM 1
MEM 2
MEM 3
This key switches the meter on or off. If the meter is on and sits idle for more
than 3 minutes, it automatically switches off to preserve battery life. When the
meter is rst switched on a battery check is made see Section 3.4 for a description
of the visual and audible low battery signal.
This key is used to enter the belt span length. The span key is held down while
the UP or DOWN keys are used to set the belt span in metres. Releasing the
SPAN key results in an audible beep to indicate the setting has been accepted.
Pressing the SPAN key alone, shows the current setting.
This key is used to enter the belt mass. The mass key is held down while the
UP or DOWN keys are used to set the belt mass in kg/m. Releasing the MASS
key results in an audible beep to indicate the setting has been accepted. Pressing
the MASS key alone shows the current setting.
Important Note:
Belt span and belt mass are required entries if tension results in force units (N or lbf)
are desired. Entries must be in SI units (m and kg/m)
This key has two functions. The rst is to increase either the SPAN or MASS
parameters when used in conjunction with these keys. The second use is to
toggle between the Hz and the newton measurement modes.
This key has two functions. The rst is to decrease either the SPAN or MASS
parameters when used in conjunction with those keys. The second use is to
toggle between the Hz and the pound measurement modes.
The memory keys allow up to 3 sets of belt parameters to be stored in the
meter registry. Pressing the MEM 1 key recalls the rst set of belt parameters
and likewise for MEM 2 and MEM 3.
To store the belt parameters to a key, the belt span and mass parameters must
rst be entered and then immediately after release of either the SPAN or MASS
keys the appropriate MEM key should be pressed. Two beeps indicate that the
parameters have been successfully assigned to the key.

7
3.2 Audio/visual display
The SKF Belt Frequency Meter is an interactive tool. It provides both visual and audible
communication with the operator. Each signal or combination of signals has a meaning. While
all these signals are discussed in other sections of this manual, a compilation of all the available
signals will be presented here.
Generally visual signals alone give measurement results while audible signals, either alone or in
combination with a visual signal, indicate some operational step.
Tension displayed
in newton
Frequency mode,
results displayed as hertz
Tension displayed
in pound-force.
Visual measurement
results
A line segment will appear to indicate the
units assocaited with the number displayed
Audible signals
Signal When Means
One Beep Upon release of “Span” key Input accepted
One Beep Upon release of “Mass” key Input accepted
One Beep While sensor is aimed at vibrating belt Measurement taken
Two Beeps Upon pushing “Memory” key after
releasing “Span” key
Span data has been stored
Upon pushing “Memory” key after
releasing 'Mass' key
Mass data has been stored
Four Beeps Combined with “0000” N display Newton result is out of range
Combined with “0000” lb display Pound result is out of range
After pushing “On” key combined with
“zero” countdown
Low battery condition
N
Hz
lbs
N
Hz
lbs
N
Hz
lbs

8
3.3 Optical sensor
The sensor uses an invisible infrared beam to
detect vibrations of the belt. A narrow angle
orange LED generated beam is provided to guide
the aiming of the sensor.
The very best signal from the belt is seen when
the sensor is held perpendicular to the belt at the
centre of the span at 9,5 mm (3/8 in) distance.
When physical restrictions are present, it is possi-
ble to get useable readings with the sensor up to
50 mm (2 in) distance from the belt and/or tipped
up to 45° from perpendicular.
It is possible to take measurements from the
edge of the belt. The toothed side of a belt is
equally acceptable as a target for the sensor.
The sensor LEDs should be kept clean by wiping
with a soft cotton cloth. Solvents are never to
be used.

9
3.4 Battery condition
When the SKF Belt Frequency Meter is rst switched on, a battery condition check is automatically
performed. A low battery condition is signalled both visually and audibly. The display window will
ash an array of zeros, starting with four and progressing to only one. There will be an audible
signal of four “beeps” as the display changes
If these signals are seen and heard, batteries should be replaced. Batteries are accessed through
the removable cover on the back of the meter. New batteries should be inserted within 30
seconds of removal of old batteries. Taking longer risks loss of any data stored by the memory
keys. Batteries are expected to provide approximately 20 hours of continuous operation before
replacement is required.
N
Hz
lbs
N
Hz
lbs
N
Hz
lbs
N
Hz
lbs
BEEP
BEEP
BEEP
BEEP

10
3.5 Charging batteries
Do not charge batteries with the sensor head attached to the meter. Do not attempt to use the
meter while batteries are being charged. Damage to the optical sensor could result.
The SKF Belt Frequency Meter is compatible with user supplied rechargeable batteries and
charging unit. A convenient 3,5 mm, positive center charging socket is located on the bottom end
of the meter body adjacent to the sensor cable plug-in port.
Batteries: 1 300 mAh minimum (user supplied)
Charging unit: 12 to 15 volt DC output (user supplied)
Connection: 3,5 mm positive tip mini plug/socket
The built in circuit of the meter controls the charging current. Charging current is internally
limited to 100 mA. Charging time is typically 12 to 14 hours for a full charge.
You may turn the unit on while charging. The meter’s software will then signal that the batteries
are charging. The display window will ash an array of zeros, starting with only one and pro-
gressing to four. There will be an audible signal of four 'beeps' as the display charges.
Suitable rechargeable batteries and charger may be obtained directly from IDS.

11
4.0 Setup and use procedure
1. Plug sensor head into meter body. This is a keyed
plug. Line it up, do not use force!
2. Turn unit on using .
3. Load span and mass data or recall previously loaded data.
To load span data simply hold down while using
or to set the number.
When the correct number appears in the display window, simply release the span key.
The unit will beep once to acknowledge acceptance of this setting.
To load mass data simply hold down while using
or to set the number.
When the correct number appears in the display window, simply release the mass key.
The unit will beep once to acknowledge acceptance of this setting.
To save individual entries into memory, press appropriate key
, or .
As soon as the span or mass keys have been released, the meter will beep twice to
acknowledge the entry into memory.
MEM 1 MEM 2 MEM 3
ON/OFF
SPAN
(m)
DOWN
(Lbs)
UP
(Hz/N)
MASS
(kg/m)
DOWN
(Lbs)
UP
(Hz/N)

12
4. Aim sensor at centre of selected belt span.
Tap or pluck the belt. The meter will beep
once to indicate that a measurement was taken.
5. Display window will show frequency result.
6. Press to toggle to newton.
7. Press to toggle to pounds.
Note: Pressing the same key a second time will return display to the hertz value.
8. Re-adjust belt tension and repeat measurement until target tension results are attained.
MEM 1 MEM 2 MEM 3
To recall stored span and mass data simply press , or .
Depending upon where you stored the data for this specic drive.
Gap 10
to 50 mm
N
Hz
lbs
N
Hz
lbs
N
Hz
lbs
DOWN
(Lbs)
UP
(Hz/N)

13
5.0 Operating tips
Here are some procedures and “best” practices that may ease use or help increase the reliability
of your belt tensioning efforts.
Take your tension reading as close to the centre of the selected span as practical.
Use the longest belt span that can be readily accessed. Minimum useable span length is equal
to 20 times the belt tooth pitch for synchronous belts and 30 times the belt top width for “v”
conguration belts. Using too short a span yields indicated tensions that may be much higher
than actual belt tension due to effects of belt stiffness.
When possible, orientate the sensor head with the long edge of the sensor parallel to the centre-
line of the belt. This tends to eliminate any non-reading conditions due to aiming error.
On new installations, rotate the system by hand at least one full revolution of the belt to seat
and normalize the components.
If the top surface of the belt is not accessible, try to beam the sensor against the edge of the belt.
The inside surface of the belt is equally acceptable.
The meter will not give a measurement for a belt under extremely low tension. Simply increase
the drive tensioning until the meter responds. The meter will beep to indicate that a reading has
been taken.
It is good practice to take three successive readings. This will show the consistency of your
methods. If the readings vary by more than 10% reassess your measurement technique.
Taking multiple readings at different belt orientations may help you identify problems with other
drive components. Tension excursions are indicative of component problems such as a belt shaft,
poorly mounted sprocket or pulley or an irregular pulley groove.
When tensioning an array of multiple V-belts, use a single belt toward the centre of the array.

14
6.0 Meter range
The SKF Belt Frequency Meter is capable of
measuring belt vibration frequencies between
10 Hz and 400 Hz.
If the measured frequency is below 10 Hz,
the meter will display “10.00” briey and
then change to “000.0”.
If the measured frequency is above 400 Hz,
the meter will display “400” briey and
then change to “000”.
On multi-shaft (three or more shafts) it may be possible to get valid measurements by selecting a
different belt span for measurement. If the measured frequency is below 10 Hz choose an avail-
able shorter span. If the measured frequency is above 400 Hz choose a longer span if available.
Based upon the measured belt frequency, the meter is capable of calculating belt tensions up
to 9 990 N (2 200 lb.). When these limits are exceeded the meter will react as previously
described.
Belt tensions greater than these values are unusual. It is therefore advisable to check that the
span and mass parameters have been entered correctly. If they are found to be correct then
check the calculation of your target values. If everything looks correct then this drive is simply
beyond the capacity of the SKF Belt Frequency Meter. The drive will have to be tensioned by
traditional force and deection techniques.
Special Note:
Tensioning a drive generally involves moving one component shaft with respect to another.
On some drives, especially larger installations, tensioning the drive will involve sufcient move-
ment that the span length is appreciably altered. Frequency (Hz) values will remain accurate but if
a precise tension value is to be calculated it may become necessary to update the span input to
reect the new shaft spacing.
N
Hz
lbs
N
Hz
lbs
A '0000' newton reading
accompanied by four
'beeps' indicates the
result is out of range
A '0000' pound reading
accompanied by four
'beeps' indicates the
result is out of range
BEEP
BEEP
BEEP
BEEP
BEEP
BEEP
BEEP
BEEP

15
7.0 Calibration
7.1 Spot check
The measurement system of the SKF Belt Frequency Meter is based upon a very stable quartz
crystal that should never wander. However, a precision mechanical resonator (tuning fork) is
included with the meter so that a calibration check at a spot frequency of 250 Hz may be per-
formed at any time.
Tap the tip of the tuning
fork on a hard surface
and then hold STEADY
in front of the optical
sensor at a distance
of 10 to 15 mm. The
meter will measure a
frequency of 250 Hz
thus demonstrating
that it is in calibration.
Results within ±1% are acceptable. There is no adjustment possible. If greater variance is experi-
enced, the meter should be returned for calibration. See section 8.2 for manufacturer’s contact
information.

16
7.2 Annual certication
Technical support relating to calibration certication and/or operation of the SKF Belt Frequency
Meter can be obtained from the manufacturer at:
[email protected]o.uk
phone: [phone]
fax: [phone]
The meter may be returned to the manufacturer for repair or recalibration at any time.
A factory calibration certicate is included with each meter. Although the very stable solid-state
quartz crystal based system is not likely to go out of calibration, some operating procedures call
for annual gauge certication. For certication/calibration purposes the meter may be returned
to the manufacturer at yearly intervals to have the meter recalibrated and certied to NAMAS/
UKAS (National Accreditation of Measurement and Sampling/United Kingdom Accreditation
Standards) standards.
The manufacturer must be contacted for detailed costs and shipping procedures prior to any
return. Contact information for Integrated Display Systems Limited (IDS) is shown in Appendix 2.
There will be a charge for these services.

17
8.0 Technical specication
Measurement range
Frequency range .................................. 10 to 400 Hz
Measurement accuracy
Below 100 Hz............................... ± 1 signicant digit
Above 100 Hz................................ ± 1%
Belt mass input range .......................... 0,001 to 9,990 kg/m
Belt span input range .......................... 0,001 to 9,99 m
Maximum belt tension display ............ 9 990 N
2 200 lb
Environmental conditions
Operating temperature ........................ +10 to +50 °C
Shipment and storage temp ............... −50 to +70 °C
Protection class...................................... IP54
Sensor
Type.......................................................... Infrared optical
IR wavelength......................................... 970 mm
Visible aiming beam.............................. Narrow angle orange LED
Housing .................................................. Machined aluminium
Cable length ........................................... 1 m
Power supply
Battery type............................................ AA (MN1500) Alkaline only
Number .................................................. 4
Expected life............................................ 20 hrs
Compartment location .......................... Back of meter
Optional rechargeable batteries
Battery type............................................ AA (1 300 mAh minimum)
Charger.................................................... 12 to 15 V DC output
Socket/polarity........................................ 3,5 mm positive centre

18
9.0 Formulae and conversions
Force conversion constants
newton x 0,2248 = lb
pound x 4,4482 = N
kilogram x 9,8067 = N
Length conversion constants
inch x 0,0254 = m
metre x 39,3701 = in
mm x 0,001 = m
Span length calculation
S =
where:
S = Span length (mm)
CD = Center distance (mm)
D = Large pulley diameter (mm)
d = Small pulley diameter (mm)
Weight (for mass calculation use)
ounce x 0,02835 = kg
pound x 0,45359 = kg
Reminder: Belt span and mass inputs to the meter must be in SI units, m for the belt span
and kg/m for the belt mass.
CD2(D - d)2
4
-

19
Appendix
1.0 Theory of operation
There is a direct relationship between belt tension and a belt’s natural frequency of vibration.
As the tension is increased, the vibration frequency also increases. The relationship between
tension and frequency has been determined to be:
T = 4ml 2f 2
Where
T = Belt tension (N)
m= mass per unit length (kg/m)
l = span length (m)
f = vibration frequency (Hz)
The SKF Belt Frequency Meter is a dual function tool. The optical sensing head uses an invisible
infrared beam to detect vibration while the integral calculator determines the time base and
performs the necessary calculations to support the results shown in the display window.
The meter may be used with all power transmission belts regardless of type or construction.

20
2.0 Limited Warranty
Limited Warranty Time of warranty is 12 months from date of original purchase provided that
proper product registration has been completed. Product registration may be completed online
at; www.clavis.co.uk/skfbeltmeter
Warranty covers defects in materials and workmanship for the device only. Warranty does not
cover accessory items such as batteries and applies only to parts that were not damaged as a
result of inappropriate handling or use. The warranty expires immediately if the device itself
is opened. Unit must be returned to Integrated Display Systems Ltd (IDS) for evaluation of all
warranty claims. Any SKF Belt Frequency Meter claimed to have a covered warranty condition
involving material or workmanship shall, upon IDS’s approval, be returned to IDS as designated,
at the Customer’s expense. Under no circumstances will liability exceed the original purchase
price of the meter. IDS reserves the right to repair or replace the unit or to refund the original
purchase price at their sole option.
Limitation of Warranty: IDS excludes any further liability for software, handbooks and information
material. Furthermore, IDS does not accept liability for damages resulting from the use of the
SKF Belt Frequency Meter.
IDS’s total responsibility and liability for any and all claims, losses and damages of any kind
whatsoever arising out of any cause whatsoever (whether under any warranty or based contract,
negligence, other tort, strict liability, breach of warranty, other theory or otherwise) shall not
exceed the original purchase price of the SKF Belt Frequency Meter in respect to which such
cause arise, and in no event shall IDS be liable for special, incidental, consequential, exemplary,
or punitive damages resulting from any such cause. No employee, agent and/or representative,
promise or agreement, except as stated herein. IDS shall not be liable for, and customer assumes
all liability for, all personal injury and property damage connected with the use of the product.
There are no warranties which extend beyond the description on the face hereof, and IDS
disclaims warranty of tness for purpose or any other implied warranties.
All rights, especially for copying and distribution as well as translation of this material are
reserved, and require written consent from IDS. Contact IDS Customer Service for warranty
claims, product return procedure or technical information.
Integrated Display Systems Limited (IDS)
Tel: [phone] Fax: [phone] www.clavis.co.uk
Information you will need to register warranty online (keep log for your records)
Date of Purchase
Serial Number (on back of unit)
Purchaser’s Name
Purchaser’s Mailing Address
E-mail (optional)
Purchased from