- 8  
 
Preparations for Inspection and Maintenance of Equipment (Powering-Off) 
 
1) Stop the equipment and check that the motor has  
completely stopped. 
 
2) Press the interlock switch on the operation panel (See Fig. 1 in the next section).  
The light on the switch should turn on. 
 
 
 
3) Turn off
 the external main power supply.  Disconnect and  lockout the main 
power. 
 
 
 
 
4) Turn off and lock out the control power supply. 
 
5) Turn off an lock out any other job specific power feeding the drive. 
 
 
 
 
 
6) Wait for 15 minutes or more for the bus to discharge. 
 
 
 
 
 
 
 
7) Verify that all power is removed by measuring the main, the DC bus, the control, 
and any other external source voltage levels with properly rated measuring 
equipment. 
Note! A meter rated for 5kV is required to safely check the main circuit 
voltages. 
 
 
 
 
8) Ground the 3-phase input power supply terminal at the main circuit input 
terminals. (Grounding is automatic when the equipment is supplied with a JK type 
incoming starter.) 
 
 
 
 
9) Perform the necessary maintenance. 
 
Stop the 
equipment
 
Main power 
OFF
 
Control power 
OFF
 
Wait for DC bus 
discharge
 
Voltage check 
Work 
Grounding