If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor_____________?
Correct answer: D. is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor
- A. of lower H.P. should be selected
- B. of higher H.P. should be selected
- C. can be used for 50°C ambient temperature also
- D. is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor
Explanation
A higher ambient temperature reduces the permissible temperature rise and therefore the motor's safe output rating. The motor must be derated according to the manufacturer and a higher-rated motor selected if necessary.
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