ZF-DUOPLAN 2K120 User manual

Operating Instructions
Two-speed Gearbox
2K120 / 2K121
08.2013 Edition
4161 758 101j_en

2K120/2K121
2
Subject to alterations in design
Copyright by ZF
Reproduction, in whole or in part, is only allowed with our written approval and authorization.
Printed in Germany
Edition: 2013-08
4161 758 101j

Operating Instructions
2K120/2K121 Contents
3
1Preface ...................................................................................................................................5
1.1Safety instructions .....................................................................................................................5
1.2ZF instructions...........................................................................................................................5
1.3Service products........................................................................................................................6
2Application and Design............................................................................................................7
2.1Application ................................................................................................................................7
2.2Features ....................................................................................................................................7
2.3Design.......................................................................................................................................8
2.4Technical data ...........................................................................................................................9
2.5Installation positions ................................................................................................................10
3Initial Installation ...................................................................................................................11
3.1Axial runout, radial runout and length tolerances – drive motor.................................................11
3.2Balancing ................................................................................................................................12
3.2.1Semi-key balancing..................................................................................................................12
3.2.2Full-key balancing....................................................................................................................12
3.3Adaptation, motor/gearbox ......................................................................................................13
3.3.1Open design............................................................................................................................13
3.3.2Enclosed design with hub bearing and oil seal..........................................................................14
3.3.3Closed design (with shaft seal).................................................................................................15
3.3.4Open design with adapter ring................................................................................................16
3.3.5Keyless hub .............................................................................................................................17
3.4Gearbox – fit............................................................................................................................18
3.5Output.....................................................................................................................................19
3.5.1Version with belt output ...........................................................................................................19
3.5.2Version with coaxial output ......................................................................................................19
3.5.3Version with TSC .....................................................................................................................19
3.6Electrical connection, gearchange............................................................................................19
3.6.1Shift unit..................................................................................................................................19
3.6.2Shift logic ................................................................................................................................22
3.7Lubrication ..............................................................................................................................23
3.7.1Splash lubrication ....................................................................................................................23
3.7.2Recirculating lubrication...........................................................................................................23
3.7.3Ports and connections for lubrication........................................................................................25

Operating Instructions
Contents 2K120/2K121
4
4Taking into Operation ............................................................................................................27
4.1Initial inspection ......................................................................................................................27
5Maintenance .........................................................................................................................27
5.1Oil change...............................................................................................................................27
6Repair ...................................................................................................................................28
6.1Gearbox fault checklist.............................................................................................................28
6.2Gearbox – disassemble............................................................................................................29
6.3Hub.........................................................................................................................................29
7Frequently Asked Questions (FAQ).........................................................................................30

Operating Instructions
2K120/2K121 Preface
5
1Preface
This documentation is intended for specialists who
have experience to carry out maintenance and
repair work.
The ZF product is documented in accordance with
the design status as of the issue date.
The following safety notices are used in these
operating instructions:
NOTE
Used to highlight special sequences, methods,
information, etc.
CAUTION
Used when incorrect and improper operating
procedures can cause damage to the product.
DANGER!
Used when due lack of care and attention
can cause injury to personnel and/or damage
to property.
ENVIRONMENTAL HAZARDS!
Lubricants and cleaning products must not be
poured onto the ground, into groundwater or
down the drain.
• Obtain and comply with the safety
regulations relevant to these products
issued by your local environmental
authority.
• Collect used oil in a suitably large
container.
• Dispose of used oil, clogged filters,
lubricants and cleaning products in
accordance with local environmental
protection regulations.
• Always follow the instructions issued
by the manufacturer when handling
lubricants and cleaning products.
1.1 Safety instructions
•All persons repairing ZF units are responsible for
their own work safety.
•Every applicable safety regulation and legal
requirement must be complied with in order to
prevent injury to personnel and/or damage to
the product during the course of maintenance
and repair work.
•Repair staff should familiarize themselves with
these regulations before commencing work.
•Correct and proper repair of these ZF products
can only be assured by appropriately trained
specialists.
•The organization in charge of repairs is
responsible for ensuring that such training is
given.
•Read these operating instructions carefully
before commencing any testing or repair work.
CAUTION
Pictures, drawings and components do not
always represent the original object but are used to
illustrate working procedures.
The illustrations, diagrams and parts are not drawn
to scale and no assumptions should be made
regarding size and weight (including within a single
illustration or drawing).
Work must be performed as described in the text.
Following the completion of repair work and
testing, the specialists must satisfy themselves that
the product will function perfectly again.
1.2 ZF instructions
•Remove any traces of old seals or gaskets
from mating faces. Use an oil stone to carefully
remove any burrs or similar irregularities.
•Carefully cover or shield open gearboxes to
prevent the ingress of foreign matter.
!
!

Operating Instructions
Preface 2K120/2K121
6
1.3 Service products
Product Name/specification Quantity
(approx.)
[dm3]
Use Remarks
Grease Shell Avania WR2
Fuchs Renolit CXEP2
Esso Beacon EP2
General purpose
Gearbox oil
HLP 68 to ISO VG 68
1.0
1.4
Gearbox oil for
splash lubrication
2K120 –
Installation pos. B5
2K121 –
Installation pos. B5
Can also be used for
recirculating lubrication
and recirculating
lubrication with heat
exchanger
Gearbox oil
HLP 46 to ISO VG 46
Gearbox oil for
recirculating
lubrication
Can also be used for
recirculating lubrication
with heat exchanger
Gearbox oil
HLP 32 to ISO VG 32
Gearbox oil for
recirculating
lubrication with
heat exchanger
Bonding agent
(liquid seal)
Loctite 574 Sealing end cover
in hub
End disc 28 DIN 470 1 Hub sealing Exchange after
disassembling the hub

Operating Instructions
2K120/2K121 Application and Design
7
2Application and Design
2.1 Application
The ZF-DUOPLAN two-speed gearbox is mainly
used in machine tool drives.
By way of example, the gearbox can be used in
turning machines (horizontal B5) or machining
centers (vertical V1) thanks to its variable
installation position. The gearbox is also suitable
for use in many systems in which torque increase
or speed reduction is required.
The gearboxes have coaxial output and are suit-
able for the high speeds generated in machine tool
construction.
2.2 Features
•Two-speed gearboxes for AC and DC main
spindle drives in machine tools
•Compact thanks to planetary design
•Flange-mountable to all AC, DC and standard
motors
•High running smoothness and low-noise
operation thanks to helical gearing
•Low torsional backlash
•Easy to install
•High radial forces permitted on output end
•Combined axial and radial force thanks to
flexible output bearings
•High efficiency
•Electromotive gearchange

Operating Instructions
Application and Design 2K120/2K121
8
2
1
3
1
2
6
1
9
1
3
2
0
17
1
8
1
6
1
0
1
1
4
5
1
4
9
7
8
2.3 Design
The gearbox primarily comprises the following
assemblies:
Connecting parts:
•Drive hub (1)
•Adapter plate (2) with radial shaft seal (3) and
hub bearings (4), as necessary
Housing:
•Gearbox housing (5)
Input:
•Sun gear (6)
•Ring gear (7)
•Ring gear bearings (8)
Output:
•Bearing housing (9)
•Output bearings (10, 11)
•Output shaft (12)
•Radial shaft seal (13)
•Planet carrier (14)
•Sun gear bearings (15)
Shift mechanism:
•Sliding sleeve (16)
•Shift fork (17)
•Brake disc (18)
Shift unit:
•Shift unit (19)
•Selector finger (20)

Operating Instructions
2K120/2K121 Application and Design
9
2.4 Technical data
Nominal power max. 19 kW
Nominal speed 1500 rpm
Input torque
(continuous operation): max. 120 Nm
Max. speed
in ratio i≠1 8000 rpm
in direct drive i=1
(with gearbox
oil cooling) 12000 rpm
See chap. 3.7.3.2 “Ports and connections for
recirculating lubrication” (values apply as of
01/2004).
NOTE
When using engine brakes/counterflow to brake
the spindles (e. g. emergency stop) ensure that
the moments of inertia do not exceed the
admissible output torques. Braking times must be
adapted accordingly.
Standard fixing dimension (in mm)
in accordance with EN 50347: 2001
Two-speed
gearbox
2K120
FF215
2K121
FF265
Motor size 100 112
h 100 112
d 28/32/38 28/32/38
l 80±0.1 80±0.1
b 180 230
e2215 265
a1– –
s214 14
Nominal input torque
(continuous operation) max. 120 Nm
Max. output torque
i = 1.00 120 Nm
i = 3.16 379 Nm
i = 4.00 480 Nm
i = 4.91 589 Nm
Weight approx. 42 kg (2K120)
approx. 52 kg (2K121)
Standard type plate
(affixed to gearbox housing)
ZF FRIEDRICHSHAFEN AG
MADE IN GERMANY
TYPE PARTS LIST
RATIO SERIAL-NO.
BACKLASH
MAX.
INPUT TURN RPM
POWER MAX.
AT RPM KW
INPUT
TORQUE NM OIL GRADE
OIL
QUANTITY
SHITING V
UNIT W
i , - ,
MIN.
S2
a1
db
h
l

Operating Instructions
Application and Design 2K120/2K121
10
2.5 Installation positions
Horizontal B5
Horizontal B5
Shift unit on right side,
gearbox turned around
longitudinal axis
(view to output end)
Vertical V1
Vertical V3
CAUTION
The breather outlet must always be at the top,
regardless of the installation position.

Operating Instructions
2K120/2K121 Initial Installation
11
3Initial Installation
3.1 Axial runout, radial runout and length
tolerances – drive motor
In order to guarantee fault-free operation, the
motor must not exceed the specified tolerances.
Axial runout, radial runout and length tolerances –
electric motor mounting flange:
Gearbox
type
Tolerance
A B C L
2K120/
2K121
0.025 0.050 0.050 ± 0.100
Tolerances A, B, C to DIN 42955R
Please note that the tolerance of the shaft length
“L” is restricted in relation to the DIN standard
CAUTION
The special tolerance for shaft length “L” must be
maintained in order to guarantee fault-free gearbox
operation. Undersize shafts must be compensated
for by using shims when mounting to the motor.
Oversize shafts must be machined to the correct
length.
Take into account the permitted axial forces
on the motor shaft. Also see ZF-DUOPLAN
catalogue (4161 750 102), “Performance data”
chapter.
Take into account the motor shaft elongation
caused by heating in motors with fixed bearing on
the B-side (opposite the motor output shaft).
ABC
L
001064

Operating Instructions
Initial Installation 2K120/2K121
12
Half-key balancing Full-key balancing
3.2 Balancing
The hubs (2) come with a keyway (1) for trans-
mitting power from the motor shaft (3) as standard.
There are two balancing types for the motor and
gearbox: Semi-key and full-key, which are
described in more detail in DIN ISO 8821.
It must be ensured that the hub is balanced in the
same way as the motor.
This is why it is very important to indicate the
motor data, dimensions and balancing type when
ordering.
Motor output shafts with standard fitted key
in accordance with EN 50347: 2001
Shaft diameter Fitted key Fitted key
length
28 mm A7x7 45 mm
32/38 mm A10x8 70 mm
42 A12x8 90 mm
NOTE
In the case of motor shafts with open ends of the
keyway, the parallel key is to be glued into the
groove in order to avoid axial migration of the
parallel key and/or the hub.
3.2.1 Semi-key balancing
In semi-key balancing, the keyway is filled with
a balance compensation corresponding to
approximately half a key, shape B by default. This
is based on the original key, shape, length and
position used by the motor manufacturer and is
defined as a counterweight. In semi-key balancing
– in contrast to full-key balancing – the joint
passes through a shared component. This means
imbalance can arise after assembly due to
tolerance factors.
As a result, it is recommended that rebalancing
should be performed after the joined parts have
been assembled.
3.2.2 Full-key balancing
In full-key balancing, the motor shaft is balanced
with a full key whereas the hub is not. The key,
shape, length and position are not important in
this case.
1
2
3

Operating Instructions
2K120/2K121 Initial Installation
13
3.3 Adaptation, motor/gearbox
The motors must have a flange-mounting option
for mounting the gearboxes.
The gearbox housing is fitted to the motor by
means of the centering adapter on the bearing
housing. This is standard.
There is also a foot mounting on the gearbox
housing for 2K120.
Different gearbox variants are used depending on
the motor type. Gearbox mounting also differs
accordingly.
Reference dimensions for hub position
Gearbox type Dimension C in mm
2K120 33.3-0.2
2K121 53.3-0.2
CAUTION
Dimension C 32.8-0.2 (2K120) or 52.8-0.2 (2K121)
in the case of motors with fixed bearing on the
B-side.
3.3.1 Open design
The open version is the gearbox without adapter
plate but with seal on the motor output shaft (2) to
prevent gearbox oil ingress.
The drive hub (1) is delivered loose with the
gearbox. Clean the fitting surfaces of the motor (3)
and drive hub. Check the motor shaft for axial and
radial runout as described in chapter 3.1. Also
lightly grease the motor shaft.
After cleaning the fitting surfaces, heat the drive
hub to approx. 120 °C from the opening and slide
it onto the motor shaft until it reaches the stop or
shim.
CAUTION
Risk of motor shaft damage if the hub is not
sufficiently heated.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 3.4.
3
6
9
2
1
11 C

Operating Instructions
Initial Installation 2K120/2K121
14
3.3.2 Enclosed design with hub bearing and
oil seal
Variant with ball bearing (4) in which the hub (1)
is additionally mounted in order to ensure more
straightforward installation. There is no longer any
need to measure the parts or to use shims,
because the hub is delivered with an adapter plate
and hub bearing in exactly the right position.
There are no internal axial forces in the
2K120/2K121 that could act on the hub.
When assembling, separate the drive hub (1) with
adapter plate (5) from the gearbox housing (6).
Clean the fitting surfaces of the motor and drive
hub. Check the motor shaft for axial and radial
runout as described in chapter 3.1. Also lightly
grease the motor shaft.
After cleaning the fitting surfaces, heat the drive
hub to approx. 120 °C from the opening and slide
it onto the motor shaft until it reaches the motor
flange stop.
CAUTION
Risk of motor shaft damage if the hub is not
sufficiently heated.
NOTE
When assembling, it must be possible to easily
slide the hub onto the motor shaft until the
adapter plate is against the motor flange.
CAUTION
Do not use the adapter plate to help slide the hub
onto the motor shaft.
Check by ensuring that the fitted adapter plate can
be turned freely. This ensures that there is no hub
bearing preload.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 3.4.
NOTE
The radial shaft sealing ring in the drive motor
must be removed on the output end when the
closed design is used.
3
10
9
1
2
5
6
11
C
7
4

Operating Instructions
2K120/2K121 Initial Installation
15
3.3.3 Closed design (with shaft seal)
This variant incorporates an adapter plate (5) with
shaft seal (7), which means that the gearbox forms
a compact, closed unit.
The adapter plate and drive hub (1) are separately
delivered loose. Clean the fitting surfaces of the
motor (3) and drive hub. Check the motor shaft (2)
for axial and radial runout as described in chapter
3.1. Also lightly grease the motor shaft.
After cleaning the fitting surfaces, place the
adapter plate with radial shaft seal onto the motor
housing. Heat the drive hub to approx. 120 °C
from the opening and slide it onto the motor shaft
until it reaches the stop or shim (13).
CAUTION
Risk of motor shaft damage if the hub is not
sufficiently heated.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 3.4.
CAUTION
Thoroughly grease the radial shaft seal and the
drive hub before installation. When installing, make
sure that the sealing lip and the radial shaft seal are
in the correct position.
NOTE
The radial shaft sealing ring in the drive motor
must be removed on the output end when the
closed design is used.
310
12
13
7
5
6
11
C

Operating Instructions
Initial Installation 2K120/2K121
16
3.3.4 Open design with adapter ring
The adapter ring allows adaptation to different
connection dimensions. A seal is required on the
motor output shaft.
The adapter ring (5) and drive hub (1) are
delivered loose. Clean the fitting surfaces of the
motor (3) and drive hub. Check the motor shaft (2)
for axial and radial runout as described in chapter
3.1. Also lightly grease the motor shaft.
After cleaning the fitting surfaces, place the
adapter ring onto the motor housing. Then heat
the drive hub to approx. 120 °C from the opening
and slide it onto the motor shaft (2) until it reaches
the stop or shim (13).
CAUTION
Risk of motor shaft damage if the hub is not
sufficiently heated.
Tighten the threaded pin (9) and secure it to
prevent it from turning, see chap. 3.4.
35
10
6
9
1
13
2
11
C

Operating Instructions
2K120/2K121 Initial Installation
17
3.3.5 Keyless hub
When mounting on motors with a smooth motor
shaft without a keyway, it is necessary to use ring
clamping elements and pressure pieces between
the motor shaft and the input hub in order to
transmit the torque. There must be a central
thread in the motor output shaft.
The mating surfaces of the motor (3), motor shaft
(2) and input hub (1) must be cleaned.
The motor shaft (2) must be checked for concen-
tricity and axial run-out in accordance with chapter
3.1.
Loosely mount the counter-holder (4), ring
clamping elements (5+6), bush (12), pressure
piece (7) and screw connection with thread lock
(8) in advance. Watch out for the position of the
ring clamping elements when doing this. First
install the inner (5) then the outer (6) ring clamping
elements in the pack on the motor shaft.
Push the input hub onto the motor shaft with or
without adapter plate (9), depending on the
version.
By hand, move the ring clamping elements into
contact using the screw connection. Tightening
the screw connection causes the hub (and the
adapter plate, if fitted) to move axially towards the
motor. Take this into consideration with a lead
dimension of +0.4 mm.
Tighten screw connection (8) to 90 Nm for M12.
Take note of the maximum torque permitted for
the thread in the motor shaft.
Screws with a strength category of 10.9 must be
used with adaptations without a coolant flow.
Check dimension C and the concentricity of the
hub.
There is no longer any need for an additional
internal seal in conjunction with ring clamping
elements. The number of ring clamping elements
and bushes can vary depending on the motor.
In screw connections with a hole for the coolant to
flow through, watch out for the O-rings and grease
them before installation.
The input hub must be blocked in order to prevent
twisting of the motor shaft and input hub when
tightening. This can be done using a special tool
ZF 1X46 190 227.
CAUTION
Do not grease the motor shaft and the hole
in the input hub! The cone surface of the ring clamp
elements also needs to be lightly oiled!
NOTE
The counter-holder is supported on the shoulder of
the motor shaft. It is necessary to have a large
contact surface.
In the closed version without hub bearing, grease
the seal running surface for the radial oil seal on
the input hub before installation. Watch out for the
position of the sealing lip when pushing on the
input hub.
CAUTION
When using the enclosed design with hub bearing
(10) and radial oil seal (11), do not push the input
hub onto the motor shaft using the adapter plate.
Once the screw connection has been tightened, the
adapter plate must be in contact with the motor
housing and it must be possible to turn it freely.
This means the hub bearing is free from tension.
36
5
56
8
8
1
7
10
9
C
11
4
2

Operating Instructions
Initial Installation 2K120/2K121
18
3.4 Gearbox – fit
The M8 set screw (9) must be screwed in and
tightened at the parallel key with 18 Nm until
firmly home. Make sure you coat the threaded
pin with liquid seal before installing it.
Make sure that the O-ring (10) is in the correct
position during installation. The O-ring is delivered
loose with the gearbox and has to be coated with
grease before being inserted into the seal groove
in the housing (6).
Check the position of the gearbox shift
mechanism. The sliding sleeve must be in the
1st gear position (“low” gear ratio).
Take up the gearbox and place it onto the motor
flange. Carefully bring the sun gear/hub
connection together when doing this.
NOTE
The external spline of the sun gear must be guided
into the internal spline of the hub. This can be
made easier by slightly turning the motor shaft
or the gearbox output to the left or right.
Hold the electric motor by the eye-bolts. Then
carefully guide the motor shaft with fitted drive
hub into the gearbox.
The gearbox housing, adapter plate and motor are
bolted together using four/eight hexagon bolts
(11).
Fill the gearbox with oil and connect up the
recirculating lubrication system and the power
supply. The breather outlet must always be at the
top, regardless of the installation position. The
breather is screwed in to the B5 position ex-works.
The gearbox is now ready for use.
CAUTION
The gearboxes can be operated under the same
degrees of protection as those defined for AC and
DC motors.
When setting up, make sure that the motor
cooling air can flow in and out unhindered.
NOTE
Before taking the electric motor/gearbox assembly
into operation, check that the gearbox output can
be turned by hand.
In the case of drive units that are fixed on the
gearbox flange or housing, the motor can be
supported on the B-side so that it does not vibrate.
1st gear position:
A Brake disc
B Sliding sleeve

Operating Instructions
2K120/2K121 Initial Installation
19
3.5 Output
3.5.1 Version with belt output
The belt pulley must be centered on the outer
diameter of the output flange (tolerance K6),
fastened with the bolts so that it is frictionally
engaged and secured. Comply with the specified
tightening torques.
The belt pulley should be balanced to quality 6.3
as per VDI Directive 2060 in order to ensure low-
vibration operation.
CAUTION
Note the maximum specified tensioning force when
tightening the belts in order to prevent bearing
overload.
The average belt force must be between the
bearings. When assembling, it must be possible to
easily slide the belt pulley onto the output shaft.
Heat the belt pulley if necessary.
3.5.2 Version with coaxial output
In the case of the version with coaxial output
(shaft stub), also note the balancing type for the
output (see chap. 3.2). The gearbox is delivered
with full-key balancing.
Refer to the installation drawing for the fitted key
dimensions. Always fix the fitted key using a
threaded pin.
3.5.3 Version with TSC
The version with TSC (Through Spindle Coolant) is
used for carrying cooling lubricant, hydraulic oils
or air/oil mixtures1) through the gearbox to the
spindle. A rotary transmission lead through is
necessary to ensure that the fluid can be conveyed
in a ratio operating at differential speed. This lead
through is subject to wear depending on the load
and the status of the medium. The warranty for the
rotary transmission lead through is limited to 12
months.
Information about the product, function, operation
and installation of the rotary transmission lead
through can be found in the operating instructions
4161 758 030 (German)
4161 758 130 (English)
CAUTION
1) No abrasive or solvent additives are permitted in
the fluids.
3.6 Electrical connection, gearchange
The gearbox is electrically connected using the
supplied 8-pole Harting connector (HAN 8 U). The
plug-in connection is located on the shift unit.
3.6.1 Shift unit
Technical data:
Standard and neutral position 120 W
Supply voltage 24 V DC ± 10 %
Power consumption 5 A
Index of protection IP64
The required cable lead diameter is 1.5 mm².
The 24 V DC connection voltage and 5 A power
consumption must be assured on the shift unit
connector.
Losses due to cable length and transition resistors
must be taken into account.
Scope of supply:
Sleeve housing, screw connection, socket insert
and 8 jacks, type Harting AWG16. The shift unit is
only available as a complete part.

Operating Instructions
Initial Installation 2K120/2K121
20
Gearbox shift mechanism:
Gearchanges are effected when the 24 V voltage
is applied to pin 2 and 3. The polarity of the
applied 24 V DC voltage dictates which gear is
engaged.
In 1st gear => Pin 2: + / Pin 3: ‒
In 2nd and 3rd gear => Pin 2: ‒/ Pin 3: +
During the gearchange, the main spindle motor
should make the shaft oscillate ±5° at a rate of 1
to 5 rotation direction changes per second. Major
pendulum motion may lead to damage at the
meshing gears.
In average, this means: nMot = 5°/s = 5° 60/min =
300°/min = 300/360 rpm = 0.83 rpm.
Conversion
Pendulum speed ↔pendulum rotary motion
Speed
[rpm]
Angle
[°/min]
Time
[sec]
Angle
[°/sec]
0.25 90 3.33 5
0.50 180 1.67 5
1.00 360 0.83 5
2.00 720 0.42 5
3.00 1080 0.28 5
4.00 1440 0.21 5
5.00 1800 0.17 5
The machine optimum is to be determined on the
basis of shift tests in relation to the different
masses and thereto connected drag torques of the
spindle.
The limit switch signals from S1 (contact 4) and
S2 (contact 6) serve to shut off the shift unit once
the gearchange is complete.
CAUTION
After the limit switch signals have been reached,
the shift unit is allowed to be live for a maximum of
0.5 second. The limit switch signals must be
monitored during the operating time.
The limit switches must only be energized with the
control current (0.1 – 0.5 A) and not with the
changeover current (5 A).
If the number of resistors is rather small, also a
lower control current can be used.
The control current for end-position monitoring is to
be set according to length, line and transition
resistance and the number of connection points.
Increased resistance due to corrosion after some
time must be taken into consideration. Switching of
inductive loads by means of the control current
requires it to be wired parallel to the load by a
diode.
If the limit switches detect that a gear is no longer
securely engaged, steps such as emergency shut-
off etc. must be initiated through the control
system.
NOTE
Electromagnetic fields can falsify the limit position
monitoring currents. This can be prevented by re-
routing or shielding the line.
The shift sequence must be monitored. If
necessary, a timer should be used to cancel the
shift sequence after approx. 2 seconds if there is
no limit switch signal (S1/S2). The main spindle
motor can not be operated until this signal is
present.
Rotation direction
changes