ABB OTM_C_21D User manual

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INSTALLATION AND OPERATING INSTRUCTION
Automatic Transfer Switch
OTM_C_21D
— Automatic Transfer switch 34OTM_C_21D rev. B / 1SCC303015M0201 / EN

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Table of contents
2
003 – 004 Symbols & Terms
005 – 008 Product overview
009 – 012 Quick start
013– 016 Interface and Settings
017 Technical data
018 – 020 Installation
021 – 022 Optional accessories
023 Maintenance and common troubleshooting
024 Appendix

3
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
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Symbols & Terms
Risk of Electric shock: Warns about a situation where a hazardous voltage may cause
physical injury to a person or damage to equipment.
General warning: Warns about a situation where something other than electrical
equipment may cause physical injury to a person or damage to equipment.
Caution: Provides important information or warns about a situation that may have a
detrimental effect on equipment.
Information: Provides important information about the equipment.
Table 1. Explanations of abbreviations and terms
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Explanations of abreviations and terms
OTM_C_21D Automatic transfer switch, the type name
LN1-Switch I Power supply line, e.g. the primary line
LN2-Switch II Power supply line, e.g. the secondary line used in emergency cases
EMERG OFF
(fire control system)
Used to drive the automatic transfer switch transfers to the “O” position when
receiving EMRG OFF signal.
AUTO Automatic mode
Remote test A sequence to test the functionality of the automatic transfer switch
Ts Switching delay
TBs Back switching delay
OV Adjustable overvoltage threshold
UV Adjustable undervoltage threshold

4AUTOMATIC TRANSFER SWITCH, OTM_C_21D
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Product overview
Product overview
The OTM_C_21D automatic transfer switch can be
used as a source transfer switch in a threephase or
single-phase networks. Monitored conditions are,
no-voltage, phase-loss, overvoltage and under-
voltage detection, transfer delays, generator start
and stop, and remote test function.
Source transfer can be performed using a manu-
ally operated handle, locally using push buttons or
fully automatically. The automatic mode includes
several operating methods: Line 1 priority, no line
priority and manual back switching mode.
The standard package includes:
1. automatic transfer switch, 2. handle, 3. handle storage clip and 4. terminal plug.
Figure 1. OTM_C_21D automatic transfer switch
1. Handle for manual operation
2. Place for auxiliary contact blocks
3. Push button
4. Mimic panel
5. Voltage sensing connections
6. Locking clip for padlock
7. Locking latch for releasing the handle and
locking electrical control
8. Locking clip for locking manual operation
9. Dip switches
10. Rotary switches
11. Connecting terminal
10 4 5
7
11
9
8 1 3 6 2

5
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
OTM_C_21D switching sequence
Line 1 Priority (default mode)
The switching sequence of OTM_C_21D can be
summarized in following steps:
The back switching sequence can be summarized
in the following steps:
• The Line 1 will start the normal functioning
• Back switching delay Tbs
• Change-over switch (Switch II) to the position 0
• Change-over switch (Switch I) to the position I
• Generator stop delay Gs
• Generator stop
Figure 2. Automatic Switching Sequences in OTM_C_21D, Line 1 priority
LN1
LN2
Switch I status
Switch II status Ts TBs
• An anomaly occurs on the Line 1 (LN1)
• Switching delay Ts, in case of phase loss, over-
voltage and undervoltage conditions
• Generator start, immediate start generator
in case of black-out, in case of phase-loss,
overvoltage or undervoltage after switching
delay Ts. (if Generator mode is selected)
• Change-over switch (Switch I) to the position 0
• Change-over switch (Switch II) to the position II

6AUTOMATIC TRANSFER SWITCH, OTM_C_21D
• An anomaly occurs on the Line 1 (LN1)
• Switching delay Ts, in case of phase-loss, over-
voltage and undervoltage conditions
• Change-over switch (Switch I) to the position 0
• Change-over switch (Switch II) to the position II
The back switching sequence can be summarized
in the following steps:
• The Line 1 will start the normal functioning
• Change-over switch stays in position II
• An anomaly occurs on the Line 2 (LN2)
• Back switching delay
• Change-over switch (Switch II) to the
position 0
• Change-over switch (Switch I) to the position I
Figure 3. Automatic Switching Sequences in OTM_C_21D, No line priority
LN1
LN2
Switch I status
Switch II status Ts TBs
Generator is disabled in no line priority.
Keep generator off in this mode.
The switching sequence of OTM_C_21D can be
summarized in following steps:
No line priority

7
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
• An anomaly occurs on the Line 1 (LN1)
• Switching delay Ts, in case of phase-loss, over-
voltage and under voltage conditions
• Generator start, immediate start generator in
case of black-out, in case of phase-loss, over-
voltage or undervoltage after switching delay
Ts (if Generator mode is selected)
• Change-over switch (Switch I) to the
position 0
• Change-over switch (Switch II) to the
position II
Figure 4. Automatic Switching Sequences in OTM_C_21D, Manual back switching mode
LN1
LN2
Switch I status
Switch II status Ts
The back switching sequence can be
summarized in the following steps:
• The Line 1 will start the normal functioning
• Change-over switch stays in position II
• An anomaly occurs on the Line 2 (LN2)
• Change-over switch stays in position II
• Change-over switch can be trans ferred
manually back to position I
The switching sequence of OTM_C_21D can be
summarized in following steps:
Manual back switching mode

8AUTOMATIC TRANSFER SWITCH, OTM_C_21D
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Quick start
To operate the switch manually:
1. Attach the handle to the switch panel. You can
attach the handle in any position.
Figure 5. Operating the switch manually
When the handle is attached, the switch will automatically be in “manual mode” with the
automatic operation disabled.
Do not tamper with wires when the transfer switch is powered on.
Before powering on the transfer switch, please manually operate it to ensure it can oper-
ates and moves normally.
Then power supply is normal and without the handle attached or EMRG OFF signals, the
switch will be in automatic mode and switch to the primary line upon initial power-up.
Keep the handle attached if you do not want the switch to be in automatic mode upon
initial power-up.
2.When the handle is attached, the automatic
transfer switch will automatically be in
Manual-mode and won’t operate automatically
in case of line failure. The AUTO LED on the
mimic panel is OFF.

9
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
To operate the switch electrically:
If the handle inserted:
1. Press handle locking clip and remove the handle
from the switch.
2. Press “AUTO” button and the “AUTO” LED will
be ON, indicating automatic mode.
Figure 6. Selecting the automatic transfer OTM_C_21D switch to Auto Mode
Automatic operation
OTM_C_21D must be in automatic mode and the
“AUTO” LED is on in order that the switch can per-
form automatic transfer cycles according to the
preset operating mode.
If handle is not inserted
1. If “AUTO” LED blinks, press “AUTO” button and
the “AUTO” LED will be ON, indicating
automatic mode.
2. Automatic operation includes three operating
modes: Line 1 priority (factory default setting),
No line priority, and manual back switching
mode.
System testing
Local test
In automatic mode, “AUTO” LED is ON and you
can transfer the switch using I, O, and II push but-
tons on the front panel of the switch. Press
“AUTO” button to return the automatic operation.
2
1
3

10 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 7. Remote test connection in OTM_C_21D
In the test sequence, the main power supply circuit will be closed.
If the test sequence is interrupted due to power failure, the automatic transfer switch will
enter "automatic mode" after power recovery.
e.g., when the switch is in Position I:
Enter test signals; the switch transfers to
Position O à to Position II à to Position O à to
Position I. Entering test signals is invalid
before the automatic transfer switch returns
to its original position.
Under test mode, press the “AUTO” button to
cancel test mode and return to automatic
mode. The “Auto” LED will be “ON” as normal.
4. After the remote test finishes, the OTM_C_21D
automatically returns to the automatic mode
(“AUTO” LED is on).
Remote test
The procedure of the remote test is as follows:
1. Connect to the remote test signal according to
Figure 7.
2. Ensure that the OTM_C_21D is in automatic
mode (“AUTO” LED is on).
3. Short circuit the remote test signal for at least
100 ms until the “AUTO” LED blinks to enter the
test mode. Under test mode, the automatic
transfer switch will simulate switching cycle
and finally return to its original position prior
to the activation of the test mode.

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AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 8. Locking the electrical operation
Ø5-6 mm
Locking the manual operation
By default, the manual operation can
only be locked in position 0. The
handle can be padlocked by pulling
out the clip from the handle and
place the padlock on the handle see
Figure 9.
1
2
3
4
Ø5-6 mm
Locking
Locking the electrical operation
The switch can be padlocked in any position,
causing that all operating modes and test
operations are disabled and handle cannot be
inserted. See below for operation:
Figure 9. Locking the manual operation

12 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
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Interface and Settings
Figure 10. Buttons
Table 2. Buttons
Transfer using buttons bypass
switching and back switching delays.
Figure 11. LEDs
Table 3. LEDs
Buttons
LEDs
LED Display Status description
LN1/LN2 ON Sourse available
Blinking Overvoltage, undervoltage or phase loss
OFF Source not available
I/II ON Switch I or II closed
OFF Switch I or II open
Blinking Switching failure
Auto ON Transfer switch in automatic mode
Blinking Transfer switch in test mode or invalid setting
OFF Transfer switch in manual mode
EMRG OFF ON Receiving emergency signals
OFF No emergency signals input
Button Function Remarks
I ON Transfer to LN1 Only available in automatic mode and remote
test mode
O OFF Transfer to 0 position
II ON Transfer to LN2
Auto Select autiomatic mode, fault clearance and reset

13
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 12. Rotary switch, Ts and TBs
Figure 13. Rotary switch, OV and UV
Rotary switch settings
1. Switching delay Ts: The delay of switcing from
primary line to secondary line in automatic
mode; Choose from 0, 1, 2, 3, 5, 10, 15, 20, 25,
and 30 seconds.
Back switching delay TBs: The delay of
switching from secondary line to primary line
in automatic mode; Choose from 0, 5, 10, 20,
30, 60, 120, 300, 600, and 900 seconds.
2. Overvoltage threshold OV (%) and under
voltage threshold UV (%): The benchmarks of
the OV and UV are the rated voltage of the
switch. When the voltage is higher than the
preset OV value or lower than the preset UV
value, the switch performs automatic transfer.
The value of OV can be 5 %, 10 %, 15 %, 20 %,
25 %, and 30 %.
The value of UV can be 5 %, 10 %, 15 %, 20 %,
25 %, and 30 %.

14 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
The 9-bit dial is used to control the switch for circuit testing, and the mismatch with
the load power supply will result in testing and transfer failure. Therefore,carefully read
this guide and set correct parameters based on the actual situation before using this
product.
Table 4. Dip switch
Dip switch setting
1. Switching delay Ts: The delay of switcing from
primary line to secondary line in automatic
mode; Choose from 0, 1, 2, 3, 5, 10, 15, 20, 25,
and 30 seconds.
DIP
No.
Function Setting
1, 2 Pole setting 01 10 11 00
2 poles 3 poles 4 poles Invalid setting
3, 4 Mode
setting
01 10 11 (default) 00
No line
priority
Manual back
switching
Line priority LN1 Invalid setting
5, 6 Voltage setting 01 10 11 00
240VAC/415VAC 230VAC/400VAC 220VAC/380VAC Invalid setting
7 Frequency setting 0 1 (default)
60 Hz 50 Hz
8Generator
selection
0 1 (default)
No Yes
9Generator stop
delay setting
0 1 (default)
240s 30 s
Figure 14. The 9-dip switch is used to set the
working modes of transfer switch

15
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Table 5. Terminals
Figure 15. Terminals
Terminal outputs and inputs
The switch has 11 bits of signal terminals for users
to input and output signals.
Terminal
No. Function
1, 2 Remote test: connection for at least 100 ms for the switch to enter the remote test mode.
3, 4 EMRG OFF: Input the 24VDC EMRG OFF signals for at least 1s until the switch transfers to the
EMRG OFF position and the EMRG OFF LED is on. At this time, the switch cannot enter the
automatic or test mode and only handle operation is allowed. After the signal is canceled,
press “AUTO” to quit EMRG OFF.
5, 6 Generator start: Dry contact, Generator start signal output. When the secondary power is a
generator, they are used to start (close signal) and stop (disconnect signal) the generator.
After the switch transfers to the primary power, the generator stop signal is sent after the
preset delay for generator stop (see the No. 9 in section 4.3 for the generator stop delay
setting).
7,8,9 Switch status, Dry contact, Switch feedback output signal to show the actual position of the
transfer switch.
10, 11 Alarm: Dry contact, The switch outputs consecutive alarm signals in EMRG OFF mode or
refuses to perform operations. The alarm signals are cleared after quitting the EMRG OFF
mode or fault recovered.
Output
contacts
Output contact relays are dry contactz and therefore external voltage supply is required.
24VDC or up to 250VAC max. 3A AC1

16 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Table 6. Technical data
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Technical data
Automatic transfer switch Parameters
Rated operational voltage Ue [V] 220~240 V AC 50~60 Hz
Operating voltage range 0.7~1.3 Ue
Measuring accuracy ±3%
Operating angle 90° ( O-I, I-O, O-II, II-O)
180° ( I-O-II, II-O-I)
OFF time 0,6 - 0,7 s
Total transfer time 2.5 s
Electromagnetic compatibility Class A
Ingress Protection Rating IP20, front panel
Rated impulse withstand voltage
Uimp
8 kV (6 kV for control circuit, disconnect the power line of
the control circuit before carrying out the dielectric voltage
withstand test)
Operating temperature -25~55 oC
Transportation and storage temperature -40~70 oC
Altitude Max. 2000 m

17
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 16. Installation of OTM_C_21D, screw.
Installation method
The switch can be installed using screws or a DIN
rail.
The fixed installation mode on the base board is
as follows:
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Installation
2
M4
4

18 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 17. Installation of OTM_C_21D, DIN rail
The DIN rail installation mode is as follows:
First pry out the latch with an appropriate tool, as
shown in Figure 17.
After attaching the switch to the DIN-rail, push
the latch back to lock it.
Figure 18. Installation of OTM_C_21D, DIN rail
After attaching the switch to the DIN-rail, make sure you push the latch back to the lock
position, otherwise the switch may fall off.
Push!

19
AUTOMATIC TRANSFER SWITCH, OTM_C_21D
Figure 19. Dimensions
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Technical data

20 AUTOMATIC TRANSFER SWITCH, OTM_C_21D
OTM32-125F2C21D
OMZC03
OTM32-125F3C21D
OTM32-125F4C21D OMZC04
Number of conductors permitted to be
clamped on the terminal ≤2
Wire specification: 10-70 mm², 8-00 AWG
17
6 Nm
Figure 20. Bridging bars
Bridging bars
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Optional accessories