電機服務係數就是指工作制式和過載率，是衡量電機連續負載工作能力的一個參數。它是為了滿足特殊套用場合而備用的一個功率係數。軸伸端就是皮帶輪或是聯軸器端也就是動力輸出端，非軸伸端一般是指散熱風扇端。
基本介紹
- 中文名：電機服務係數
- 性質：工作制式和過載率
- 作用：衡量電機連續負載工作能力
- 目的：滿足特殊套用場合
概念,Example - Service Factor,舉例,
概念
The service factor - SF - is a measure of periodically overload capacity at which a motor can operate without overload or damage. The NEMA (National Electrical Manufacturers Association) standard service factor for totally enclosed motors is 1.0.
A motor operating continuously at a service factor greater than 1 will have a reduced life expectancy compared to operating at at its rated nameplate horsepower.
NEMA Service Factor at Synchronous Speed (RPM) for drip proof motors:
Power (HP) | Service Factor - SF | |||
Synchronous Speed (RPM) | ||||
3600 | 1800 | 1200 | 900 | |
1/6, 1/4, 1/3 | 1.35 | 1.35 | 1.35 | 1.35 |
1/2 | 1.25 | 1.25 | 1.25 | 1.25 |
3/4 | 1.25 | 1.25 | 1.15 | 1.15 |
1 | 1.25 | 1.15 | 1.15 | 1.15 |
1 1/2 and up | 1.115 | 1.15 | 1.15 | 1.15 |
Example - Service Factor
A 1 HP motor with a Service Factor - SF = 1.15 can operate at
1 HP x 1.15
= 1.15 HP
without overheating or otherwise damaging the motor if rated voltage and frequency are supplied to the motor.
Insulation life and bearings life are reduced by the service factor load.
舉例
如果是30Kw的電機，如果係數是1.15，那么它的實際功率是30×1.15=34.5Kw
工作制式有連續工作，短時工作，間歇工作，過載率是指電機超過額定負載的能力，服務係數是一個綜合指標，一般式s1--s9，過載係數一般式1.15-1.2。
