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交流风扇必须满足附录B中的B4(过载运转试验)和B5(堵转试验)要求。除非以下情况,可以不用做B4试验:" d C) R, h/ p
– motors that are used for air-handling only and where the air propelling component is3 W' V' Y5 b1 m( ]& u
directly coupled to the motor shaft; and
, a$ j5 P0 \' t4 ?4 C– shaded pole motors whose values of locked-rotor current and no-load current do not differ
$ D5 m( C* z* d7 ^) T4 h5 Wby more than 1 A and have a ratio of not more than 2/1. - _8 T: }2 g3 a# f# C$ f
3 z* g) r; X9 X a
对于温升限制,标准要求B4试验和B5试验电动机绕组分别不超过表格B2和B1的要求。而堵转的试验时间是根据电动机的保护方式来选择的:
* O; d8 d H$ i3 Q" ~– a motor protected by inherent or external impedance is operated with its rotor locked for
& L; `2 A1 [, e15 days except that testing may be discontinued when the windings of the motor, of either 1 Q) B% t8 q; Q, e4 d) S
the open or totally enclosed type, reach a constant temperature, provided that the
2 C/ Z3 ~0 [; r- a" y' sconstant temperature is not more than that specified in 4.5.3, Table 4B for the insulation
( R* a5 w9 \$ Osystem used;
6 M- K" d/ j2 m M) c, `– a motor with an automatic reset protection device is cycled with its rotor locked for ( I7 K+ b4 B) z
18 days;
0 X" s2 s6 |, I1 j5 S- i– a motor with a manual reset protection device is cycled with its rotor locked for 60 cycles, 5 I/ l9 B1 q- \# X
the protection device being reset after each operation as soon as possible for it to remain ( H) f+ x$ {, Y5 i8 G7 Q
closed, but after not less than 30 s;
& m; ~2 T/ N! J! w# j– a motor with a non-resettable protection device is operated with its rotor locked until the
5 i$ [# x9 I/ N. ?+ hdevice operates.0 N( f3 C, b2 \& i7 L
) N- Z$ B, g1 D/ `0 B* S对于情况一,若固有阻抗或外部阻抗保护的电动机需要堵转方式工作15d,但对开启式或全封闭式的, t! Z% H l% S3 `
电动机,当其绕组温度达到稳定时,就所采用的绝缘结构而言,如果该电动机的稳定温
6 A. Z! l/ n3 a* Q' S度不大于4.5.3的表4B规定的温度,则试验可以结束) i# b: `+ |, b9 L
( T% K7 i5 `, a一切都还需要LZ对电动机的保护方式进行判断先 |
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