User`s manual

Maintenance and Inspection

7-4

7. Maintenance and Inspection

7.3 Megger test and breakdown voltage test

Do not perform a megger test or voltage breakdown test. Semiconductor devices used in

the inverter main circuit may deteriorate if subjected to such a test.

7.4 Checking the inverter and converter

• Use a tester or multimeter to check whether the module will operate correctly.

[Preparation]

1. Disconnect the externally connected power cables (L1, L2, L3, L1C, L2C), motor

connection cables (U, V, W), regenerative braking resistor (+) and RB, and external

DC power supply cables (+) and (–).

2. Prepare an analog tester or multimeter. (Use the 1-ohm resistance measurement

range.)

[Check method]

Measure the continuity at L1, L2, L3, U, V, W, RB, (+), and (–) on the robot driver

terminal block by alternately changing the polarity on the tester to determine if module

operation is satisfactory.

Note 1: First, measure the voltage across the (+) and (–) terminals on the terminal

block of the robot driver by using the DC voltage range on the multimeter to

make sure the smoothing capacitor is fully discharged. Then switch the

multimeter to measure resistance and start making the checks.

Note 2: In the non-conducting state, the reading should be nearly infinite. However,

the reading might not be infinite due to momentary conduction caused by

effects of the smoothing capacitor. In a conducting state, the reading is

usually several to several dozen ohms.

The reading might not always be the same depending on the device type and

tester. However, the reading is satisfactory if equal to other values.

Note 3: Remove the cables from (+) and (–) on the main circuit terminal block (all

models) and also remove the shorting bar or wire connected across terminals

B1 and B2.

Note 4: The robot driver has an internal DB circuit between the main circuit

terminals U and W, so the reading measured across the main circuit terminals

is different from those shown in the table.