Extended Transfer Time Relay; Accessory Connections; Controller Powerup/Reset - Kohler MPAC 1500 Manual

1.2

Extended Transfer Time Relay

The extended transfer time relay is provided on
closed-transition transfer switches.
provided to prevent paralleling the standby and utility
sources for longer than the acceptable time if the
closed-transition transfer time exceeds 100 ms.
See the transfer switch installation manual for
connection instructions.
The relay operation time is adjustable between 100 ms
and 10 seconds. The time settings are in percent (%) of
the maximum setting, which is 10 seconds, and
adjustable in 5% increments. See Figure 1-4. The
recommended setting is 1% = 0.1 seconds. If it is
necessary to set the relay to a longer time, ensure that
the time setting is in accordance with applicable codes.
The relay activates only if the closed-transition transfer
time exceeds the set time. A Fail to Open Source1 (or
Source2) fault message will display on the ATS
controller. Identify and correct the cause of the source
disconnect problem before resetting the fault.
Setting*
1 %
50 %
100 %
* Settings above 1% are adjustable in 5% increments.
Figure 1-4 Relay Transfer Time Settings
1
1. Extended transfer time relay
Figure 1-5 Extended Transfer Time Relay
TP-6714 4/10
The relay is
Time
0.1 seconds (100 ms)
5 seconds
10 seconds
TP-6714
1.3

Accessory Connections

See Section 8 and the transfer switch wiring diagrams
for accessory connection instructions.
1.4

Controller Powerup/Reset

Following is an explanation of the sequence of operation
for the MPACt 1500 ATS Controller when power is
initially applied to the controller or a controller reset
occurs.
1. Controller self test is executed.
2. System parameters
nonvolatile memory.
3. Contactor position and source availability are
determined.
4. If neither source is acceptable, the contactor does
not change position.
5. If both sources are available, the controller
immediately transfers the contactor to the
preferred source.
6. If only one source is available, the controller
immediately transfers the contactor to that source,
executing only the off-position and load control
time delays.
If the available source is the preferred source, and
the contactor is in the standby position, the
contactor transfers to preferred, the engine
cooldown time delay runs, and then the engine
start contacts open.
If the available source is the preferred source and
the contactor is already in the preferred position,
the engine start contacts open immediately,
bypassing the engine cooldown time delay.
are downloaded from
Section 1 Installation 13