Megger Test - Omron M1 Series User Manual

10 Maintenance and Inspection
Inspec-
Inspec-
tion cat-
tion item
egory
Motor General
Isolation
resist-
ance
*1. The capacitor service life is influenced by the ambient temperature.
For inverter replacement guidelines, refer to A-8 Smoothing Capacitor Life Curve on page A-291.
*2. The life of the cooling fan depends on environmental conditions, such as the ambient temperature and/or
dust. Check the operating conditions in daily inspection.
10-1-5

Megger Test

Before performing a megger test on external circuits, be sure to disconnect all the terminals of the in-
verter and not to apply the test voltage to the inverter. Use a 500 VDC megger for a megger test.
For a megger test on the inverter main circuit, short-circuit the terminals L1/R, L2/S, L3/T, U, V, W, DB,
P1, P(+) and N(-) with wires, as shown below.
Because the insulation resistance rating of the single inverter unit is 5 MΩ or higher, it is normal if the
resistance is 5 MΩ or higher.
• For the inverter, do not perform a megger test on the control circuit. Perform it only on the main cir-
cuit.
• Use a tester (in a high resistance range) for a power-on test on the control circuit. Do not use a
megger or buzzer.
10-6
Inspec-
tion fre-
quency
Inspection
Peri-
point
odic
There is no ab-
normal vibra-
tion or sound.
There is no ab-
normal odor.
Perform meg-
ger check
(between mo-
tor terminals
and ground ter-
minal).
Inspection method
Perform acoustic, No faults
sensory and visual
inspection.
Check for abnormal No faults
odor due to over-
heating, damage,
etc.
Disconnect wires 5 MΩ min.
from the inverter
main circuit terminals
U, V, W and short-cir-
cuit the three-phase
motor wires. Then,
use a megger to
measure the resist-
ance between each
motor wire and the
ground terminal.
M1 Series EtherCAT Type User's Manual (I670)
Criteria Meter
500-VDC
class
megger