Kohler G220 User Manual

TP-6322 9/0412 Section 3 Scheduled Maintenance
Contactor Inspection. Remove the covers or arc
chute assemblies at the front of the contactor and
inspect the main contacts inside the contactor. See
Figure 3-3. Remove surface deposits with a clean cloth.
Do not use emery cloth or a file. If the contacts are
pitted, show signs of overheating, or are worn, replace
the contactor assembly. See Figure 3-4 for how each
pole of the main contacts should appear when closed.
The contacts are worn if the contact surface material, a
layer of silvery-colored metal, is removed.
Signs of Overheating. Replace components damaged
by overheating and locate the cause of the overheating.
Overheating could be caused by loose power
connections, overloading, or a short circuit in the
system. After tightening power terminals perform a
millivolt drop test to locate areas with high contact
resistance. See Section 3.2.3. Check the line circuit
breakers in the system to be sure that they do not allow
the load to exceed the switch rating. Use the controller
troubleshooting and schematics to locate a control
circuit short.
1
tp5992
1. Cover retainer
Figure 3-3 Contact Cover and Retainer, Model
G220
5992301
1
2
1. Stationary contact surface material (normal and
emergency)
2. Moving (center) contact surface material
Figure 3-4 Main Contacts
3.2 Testing
Periodic testing is important in any transfer switch
application. It helps to ensure that the generator will
start and the transfer switch mechanisms and control
circuits will operate when needed.
3.2.1 Weekly Generator Set Exercise
Use the plant exerciser to start and run the generator set
once a week to maximize the reliability of the emergency
power system. See Section 2.
3.2.2 Monthly Automatic Operation Test
Test the transfer switch’s automatic control system
monthly. See Section 2. Verify that the expected
sequence of operations occurs as the switch transfers
the load to the emergency source when a normal source
failure occurs or is simulated. When the switch transfers
the load to the emergency source, end the test and verify
that the expected sequence of operations occurs as the
transfer switch retransfers to the available normal
source and signals the generator set to shut down after a
cooldown period.

Kohler G220 Specifications

General

Brand	Kohler
Model	G220
Category	Switch
Language	English