NANO

622

ELECTRICAL

Rectifier assembly check:

Remove the rectifier assembly from the unit and

check as follows:

(a) Testing of positive heat sink diodes

(i) Continuity check

Connect as shown in figure 55. Use multimeter

with two probes. Connect the negative probe of the

multimeter to positive terminal and positive probe

to phase connecting points one by one on the

rectifier assembly. It should not indicate open

circuit. Replace the rectifier assembly if it is open

circuit.

(ii) No Continuity check

Connect as shown in figure. Use multimeter with

two probes. Connect positive probe of multimeter

to positive terminal and negative probe to phase

connector points one by one on the rectifier

assembly. All diodes should indicate no continuity.

If there is continuity it indicates short circuit.

Replace the rectifier assembly

Using 230 volt AC main supply connect a 15W

bulb as shown in figure. Connect one of the probes

to the slip ring and the other to the shaft. The lamp

should not glow. If the lamp glows it indicates

earthing. Replace the rotor assembly.

•

Stator insulation test:

Using 230 volt AC main supply connect a 15W

bulb, Connect one of the probes to any of the three

leads and the other probe to the body. The lamp

should not glow. If the lamp glows it indicates poor

insulation. Replace the stator assembly.

•

Stator winding resistance check

Use Ohm meter with two probes connect lead 3

and lead 1. The Value should read around 0.180 to

0.202 Ohms at 20°C. Repeat it between star

connection and lead 2 and 3.