On 05/15/2015 10:41 AM, Stephen Dubovsky wrote: > Hmm. Don't think so. Series motors run crazy RPM when load is removed due > to field weakening and will always vary RPM based on load. A typ handheld > corded drill has a pretty set top speed and doesn't bog until you really > start to lean on it. That would indicate to me parallel wound. > > Take apart any vacuum cleaner motor, electric drill or other hand power tool, etc. They are all wired in SERIES. These motors are designed so that the voltage across the field is relatively small, most of the voltage is across the armature. When run on AC, the phase shift assures that adequate excitation is on the field. But, series DC motors have been made for well over 100 years, and while they do droop in speed when loaded, they do not explode when unloaded.
See the Wikipedia article if you don't believe me : http://en.wikipedia.org/wiki/Universal_motor Shunt-wound DC motors that run from a stiff bus have much better speed regulation that series wound, and WILL run away explosively if the field circuit fails for any reason. That's why they have field safety relays for larger shunt-wound motors. Jon ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
