Toshiba MCY-MHP0806HT8-C Series Service Manual page 117

Points to Note When Servicing Compressor
(1) When checking the outputs of inverters, remove the wiring from the compressors.
How to Check Inverter Output
(1) Turn off the power supply.
(2) Remove compressor leads from the IPDU P.C. board (A3-IPDU). (Be sure to remove all the leads.)
(3) Turn on the power supply and start cooling or heating operation.
Be careful not to make simultaneous contact with two or more ring tongue terminals for compressor leads
or a ring tongue terminal and some other object (e.g. the unit cabinet).
(4) Check the output voltage inverter-side (CN201, 202, 203).
If the result is unsatisfactory according to the judgment criteria given in the table below, replace the IPDU P.C.
board.
No. Measured leads
1 Red-White
2 White-Black
3 Black-Red
* When connecting the compressor leads back to the compressor terminals after checking the output, check
the faston connectors thoroughly to ensure that they are not crooked. If there is any loose connector, tighten
it with a pair of pliers, etc. before connecting the lead.
How to Check Resistance of Compressor Winding
(1) Turn off the power supply.
(2) Remove compressor leads from the compressors.
(3) With compressor, check the phase-to-phase winding resistances and winding-to-outdoor cabinet resistance
using a multimeter.
• Earth fault?
It is normal if the winding-to-outdoor cabinet resistance is 10 M
• Inter-winding short circuit?
It is normal if the phase-to-phase resistances are in the 0.3-0.6
How to Check Outdoor Fan Motor
(1) Turn off the power supply.
(2) Remove fan motor leads from the IPDU P.C. board for the outdoor fan (CN750 (Under side FM), CN700 (Upper
side FM)).
(3) Rotate the fan by hand. If the fan does not turn, the fan motor is faulty (locked up). Replace the fan motor.
If the fan turns, measure the phase-to-phase winding resistances using a multimeter. It is normal if the
measurements are in the 15.6-19.0
Criterion
320 - 480V
320 - 480V
320 - 480V
range. (Use a digital multimeter.)
or more.
range. (Use a digital multimeter.)
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