3 Installation
3.7 Insulation testing
DB1 variable frequency drive
11/20 MN040031EN
Eaton.com
80
3.7 Insulation testing
The variable frequency drives of the DB1 series are tested, delivered and
require no additional testing.
If insulation testing is required in the power circuit of the PDS, you must
consider the following measures.
Testing the motor cable insulation
▶
Disconnect the motor cable from the connection terminals U, V and W of
the variable frequency drive and from the motor (U, V, W). Measure the
insulation resistance of the motor cable between the individual phase
conductors and between the phase conductor and the grounding con-
ductor.
The insulation resistance must be greater than 1 M
Ω
.
Testing the mains cable insulation
▶
Disconnect the power cable from the mains supply network and from
the connection terminals 1/L, L2/N and L3 of the variable frequency
drive. Measure the mains cable’s insulation resistance between the
individual phase conductors and between each phase conductor and the
protective conductor.
The insulation resistance must be greater than 1 M
Ω
.
Testing the motor insulation
▶
Disconnect the motor cable from the motor (U, V, W) and open the
bridge circuits (star or delta) in the motor terminal box.
Measure the individual motor windings’ insulation resistance.
The measurement voltage must at least match the rated operating
voltage of the motor but is not to exceed 1000 V.
The insulation resistance must be greater than 1 M
Ω
.
CAUTION
On the control signal and the connection terminals of the varia-
ble frequency drive, no leakage resistance tests are to be perfor-
med with an insulation tester.
CAUTION
Wait at least 5 minutes after switching the supply voltage off
before disconnecting one of the connection terminals (L1/L, L2/
N, L3, DC+, BR) of the variable frequency drive.
￫
Take the instructions from the motor manufacturer into account
when testing the insulation resistance.
