7-1
AC Induction
To prevent potential problems and provide long periods of trouble-free operation, the following checks should be
periodically conducted.
CAUTION: Do not conduct any inspections until after disconnecting
the power supply and after the “CRG” light on the Drive has gone out.
MEGGER TEST
1. Disconnect all Drive terminals and never apply test voltage to the Drive when conducting an external circuit
megger test. Use a 250 VDC megger for 230/240V input Drives and a 500VDC Megger for 480V input Drives.
2. Perform the test only on the main circuit as shown in Figure 7-1 when conducting a megger test on the Drive itself.
— Do not conduct a megger test on the control circuits.
— Short L1, L2, L3, U, V, W, P1, P(+), and DB, then megger to the Drive ground terminal E(G).
3. Use a high resistance range type tester to conduct a continuity test on the control circuits and not a megger or
a buzzer.
PERIODIC PARTS REPLACEMENT
The life of the Drive will vary according to the installation environment and the amount of running time. However, if
continuous operation is within the allowable limits, the life of the DC Link capacitor is approximately five years and
the life of the cooling fan is approximately three years. It is recommended that these parts be replaced before failure
occurs.
Figure 7-1. MAIN CIRCUIT MEGGER TEST CONNECTIONS
Section 7
MAINTENANCE and INSPECTION
MEGGER TEST OUTLINE
POWER
MEGGER
GROUND
L1
L2
L3
U
V
W
E (G)
P(+) DB
IM
•
}
•
IF SINGLE PHASE
Motor
+
–
+
–
P1 •
•
•
•
•
•
•