X20AI1744
三相异步电动机转速公式为：n=60f/p(1-s)
f代表电源频率
P为极对数
n'代表转差率
s代表转差率
三相异步电动机转速是分级的，是由电机的“极数”决定的。
三相异步电动机“极数”是子磁场磁极的个数。定子绕组的连接方式不同，可形成定子磁场的不同极数。选择电动机的极数是由负荷需要的转速来确定的。电动机的电流只跟电动机的电压、功率有关系。
三相交流电机每组线圈都会产生N、S磁极，每个电机每相含有的磁极个数就是极数。由于磁极是成对出现的，所以电机有2、4、6、8……极之分。
在，电源频率为50赫，所以二极电机的同步转速为3000转/分，四极电机的同步转速为1500转/分，以此类推。异步电机转子的转速是低于或高于其旋转磁场的转速，异步之名由此而来。异步电机转子转速与旋转磁场转速之差（称为转差）通常在10%以内。
因为如此，所以三相异步电动机的实际转速会比上述的同步转速偏低。如6的同步转速为1000转，其实际转速一般为960转/分钟。
CISCO 3620 Router + 2 x WIC-1T + BRI 4B-S/T + IE-2W
CISCO Catalyst WS-C4000 4006 WS-X4013 WS-X4124 WS-X4232
Cisco 2621 Router 2Ports Fast Ethernet cisco2612-DC
Router Cisco 2600 Series - 2613 - WIC 2T - WIC 1B S/T
CISCO WS-C6009 loaded with WS-X6348
Cisco 2612 Router + wic1T, wic2T, en pri 1ce1B
Cisco 2612 Router + Modems 8AM
CISCO 7500 Series
Cisco 7206 VXR Router P/N 47-2953-01 REV G0
CISCO 805 Ethernet Serial ROUTER CISCO 800
Cisco 3640 Series 1FE2W,Serial 4T,PRI 1CE1B
Cisco 3640 Series 1FE1R2W, PRI 1CE1B, Serial 4T
Cisco 3640 series P/N 47-5582-04 REV AO 2FE2W
Cisco 3640 series P/N 47-5582-05 REV AO 1FE1R2W, 2FE2W
Cisco 3640 series P/N 47-5582-01 REV AO 1E1R(x2
Cisco 3640 series P/N 47-5582-01 REV AO 2FE2W(x2)
Cisco 3640 P/N 47-5582-05 REV AO 1FE1R2W, 1E2W
Cisco 3640 Series 1FE1R2W,Serial 4T,BRI 4B-S/T,2FE2W
Cisco 3640 series 1FE1R2W, Serial 4T, BRI 4B-S/T, 2FE2W
Cisco Systems SRW2024P-EU Gigabit Switch 24port
Cisco Systems AIR-LAP1131AG-E-K9
CISCO 836 ADSL ISDN BROADBAND ROUTER CISCO836-K9
Cisco Redundant Power Supply 600 W Total Output -RPS600
Cisco Redundant Power Supply 600 W Total Output -RPS600
Cisco 801-805 IP/Firewall Plus CD08-CHL-12.0.7 NEW
Cisco 2651 Router + Serial 4T + 1FE 2W W1 + PRI 1CE1B +
Cisco 1712 VPN/9
CISCO Lightstream 1010 - LS1010
CISCO VCO 4K Series - Open Programmable SWITCH
CISCO VCO 4K Series - Open Programmable SWITCH
Cisco ISDN BRI RJ45 Network Cables Orange CAB-S/T-RJ45
Cisco Redundant Power System 675 - RPS675
CISCO Catalyst 5505 Series - WS-C5505
CISCO Catalyst 3900 Series - WS-C3900
CISCO Catalyst 5000 - WS-C5000 Series
Cisco 1841 - 128D/64F - WIC-1T
CISCO Catalyst WS-C6500 Series loaded - WS-X6K-SUP2-2GE
Cisco Secure PIX 525 Series FireWall 47-4827-03
CISCO Catalyst 5500 Series
CISCO 1801/K9 ISR ADSL
Cisco 3640 Router + Serial 4T + 1FE 2W W1 + PRI 1CE1B +
CISCO ASA 5510 SECURITY PLUS LICENCE
cisco secure PIX-535
CISCO WS-C3550-24PWR-?SMI PoE 3550 SWITCH
CISCO CATALYST 2960 48 10/100 BT PORTS WS-C2960-48TC-L
CISCO Catalyst 2960 G-24 TC-L Switch G-24TC-L
