dc variable speed motor power supply

Thread Starter

akolo georges

Joined Jan 7, 2011
1
i want to power my small homemade lathe with universal motor commonly used in sewing machines, i need to produce a dc supply to power it. from 220v main supply
 

PackratKing

Joined Jul 13, 2008
847
i want to power my small homemade lathe with universal motor commonly used in sewing machines, i need to produce a dc supply to power it. from 220v main supply
For starters, if truly a sewing mach. motor, the bulk of those are meant to run on 120vac, via an footpedal rheostat.........which would provide quite a wide window of speed control for a small lathe. So why would you want to bother with a DC arrangenent ??

I use a converted {{ rewound with a heavier duty Nichrome spring for better amps }} sewing mach. footpedal rheostat to provide speed control for my 120vac Dremel, also a 'universal motor' -- which works like a charm.
 

Jaguarjoe

Joined Apr 7, 2010
767
Buy or build a full wave light dimmer. Dimmers work well with universal motors. I had one on my hand drill for ages.
There are tons of circuits on the web.
You DO have an isolation transformer, right? Experiencing the wrath of unbridled mains power will garner your respect in a flash-a big flash.
 

Jaguarjoe

Joined Apr 7, 2010
767
The transformer will only deliver as many volt-amps as it is rated for (without burning up). If you have a 240VA transformer operating with a 120v constant voltage main (like a normal main would be), you can tax the secondary for 2amps max (120 * 2 = 240). The primary will then consume an equal 240 VA from the main. A smaller xfmr will have less VA and correspondingly less current to use.
 

Adjuster

Joined Dec 26, 2010
2,148
The sewing-machine motor could be designed for 120V, 220V, 240V or some other value, depending where it was designed to be used and with what type of controller. It would be a good idea to check the motor rating, rather than making any assumptions about it
 
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