Drive Circuit - Hitachi RAF-25RPA Service Manual

8. Outdoor DC Fan Motor control circuit
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DIRECT CURRENT Id
The external fan motor is controlled by the outdoor microcomputer.
This outdoor fan motor estimates the actual speed, based on the DC current flowing to R741; it then
adjusts this value as necessary, so that it becomes the speed corresponding to the operation command
transmitted from the indoor unit. In addition, overcurrent detection and other fault detection is
performed, based on the DC current.
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DRIVE CIRCUIT

MICROCOMPUTER
Fig. 8-1
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70
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FAN MOTOR
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