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Message No. 16362, Started by gerdb on 06/30/05
 amperage of fuse (circuit breaker) required I have an electric motor that draws 220 volt 3 phase 20 amp (vacuum pump for air).  It keeps on blowing the circuit breaker within seconds of start up.  What is the minimum amp required for the circuit breaker ? that is the answer I am looking for, but I am also curious about what the answer would be for a single phase motor ? Thanks in advance
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Follow-up Messages (14)
 I have no actual experience with this, but if I recall my electronics from ... No. 16404, Posted by rorschach on 07/05/05, 13:53 PST. Sam: simple question for you... What equipment/methods/procedures are used... No. 16395, Posted by rolschwarz on 07/03/05, 05:50 PST. Did you review the website I referred to earlier? It explains a lot. Agai... No. 16394, Posted by rolschwarz on 07/03/05, 05:40 PST. What is a "controller" ? My idea whould be to go with a 140 amp breake... No. 16393, Posted by gerdb on 07/02/05, 21:36 PST. Ooh, can't believe I blew that. V = I*R --> I=V/R. More resistance still ... No. 16392, Posted by rolschwarz on 07/02/05, 18:07 PST. Ohm's law is: V = I*R, so it looks to me like you got the impedance on the ... No. 16391, Posted by sdoughty11 on 07/02/05, 15:47 PST. Anyhoo, Gerd, the short answer to your question is that a bigger breaker or... No. 16390, Posted by rolschwarz on 07/02/05, 13:11 PST. Hmm.. let me think... Ohm's law... current = voltage * impedance... By y... No. 16389, Posted by rolschwarz on 07/02/05, 11:27 PST. Rolschwarz: You are way off base. I have not forgotten Ohm's law at all... No. 16386, Posted by sdoughty11 on 07/01/05, 18:53 PST. for the "Google imapired": http://www.lmphotonics.com/m_start.htm No. 16385, Posted by rolschwarz on 07/01/05, 18:38 PST. You're forgetting Ohm's law. More resistance = less current @ same voltage.... No. 16384, Posted by rolschwarz on 07/01/05, 18:05 PST. Rolschwarz: This effectively reduces the voltage across the motor until suc... No. 16383, Posted by sdoughty11 on 07/01/05, 14:28 PST. Some old plants had motors with special resistors that were placed in the c... No. 16380, Posted by rolschwarz on 07/01/05, 10:51 PST. Gerdb: The starting current for an across the line start on a 3 phase motor... No. 16371, Posted by sdoughty11 on 06/30/05, 17:03 PST.