Kitebuilder Online

CJQ · Posted: Tue Apr 06, 2004 10:22 pm Post subject: search for an electronic expert

Need some help trying to power my singer with D.C. . The motor in most home sewing machines is a universal series type that will function on both a/c or dc current . D.C. current is a more efficient current that will cause the motor to run smoother and produce slightly more power. My intent is primarily to make the machine run without motor hum ond improve its torque. I went to radio shack bought a full wave bridge rectifier wired it up and tried it out ---not too succesfuly. The foot speed controler is an SCR and is not compatable with a D.C. supply . I believe i'm on the right track but need some expert guidance.
Anyome out there that can help?
Thanks

CLIFF

smarties · Joined: 05 Nov 2003 Posts: 493 Location: Dieppe, NB, Canada

CJQ,
If you want to control the motor speed using DC voltage, you will need a PWM (Pulse Width Modulation) circuit. If you do a search on the Internet, you should be able to find some circuit examples. Make sure that the circuit can supply the power that you motor needs.

What's the DC voltage you need for your motor?

Smarties Razz

CJQ · Posted: Wed Apr 07, 2004 7:53 am Post subject: D.C. Singer power

Hi smarties, our comercial power down here is 125 vac 60 cps . I would supply line voltage rectified . The foot controler has a small print board with a v. r. slider connected to the foot pad. I believe the controled output power is half wave and that causes the motor to pulsate . The pulsation is most noticable at the start of a stich run. The foot controler is connected in series with the load. One solution would be to use a wire wound v. r. foot control and just use d.c. as a supply . Do you think the pwm produces a continous current flow or is it choppy?

CLIFF

smarties · Joined: 05 Nov 2003 Posts: 493 Location: Dieppe, NB, Canada

The PWM is a clock pulse (square wave) where the ON time vs the OFF time varies to change the power output. For example 50% ON = 50% power, 60% ON = 60% power....

But usually, the PWM circuit has a low pass filter at the output to convert the square wave signal to an analog DC voltage.

As a starting point if you want to build the circuit yourself, you can try at
TL494 (Texas Instrument)
or
TL494 (ON semiconductor)
It's an old part but still being used and available from electronics suppliers.

In you case, you would probably need a larger DC voltage output. Check what is the DC voltage and wattage(or current) you need for your motor.

If your Singer sewing machine can accept DC voltage, doesn't Singer has a DC foot pedal for it?

Smarties Razz

Kitesquid · Posted: Wed Apr 07, 2004 9:54 am Post subject:

Or your sewing machine mechanic may be able to tell you if a conversion kit is avaiable...

Or just buy a new/used machine but that can be big $$$$$$$$$$$$$$$$

btw HERE is a guy who streatched a sewing machine for his wife's quilting efforts as the manufactured large machines are $$$$$$$$$$$.

Neat tinkering he did!!!!!!!!!!

He also installed a motor controler into it, but he has other things he wants to do to it too...

READ it!!!!!!!
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

P.S. Yet another long winded post by the Squid..... Shocked

P.P.S. The wind is like the air, only pushier.

Dennist3 · Posted: Wed Apr 07, 2004 12:05 pm Post subject:

OH That is Too Cool!!!!!

Hmmmmm... this could be interestin....Squid you thinking what I'm thinking?

Dennis

Kitesquid · Posted: Wed Apr 07, 2004 12:46 pm Post subject:

Dennist3 · Posted: Wed Apr 07, 2004 1:12 pm Post subject:

CNC sewing machine idea too

CNC?

Dennis

knotronda · Posted: Thu Apr 08, 2004 2:19 am Post subject:

I love reading all the techno stuff. Don't really understand it but it is interesting. BTW my husband has a ShopBot Personal Robotic Tool and it is wonderful. (Don't get silly guys!) He has done many things with it from nametags to cabinets. One of his best items is wooden line winders that he engraves the event name and date on. Claudio Capelli from Italy was at WSIKF last summer and he and Lindsey (the husband) became aquainted. Lindsey wound up with a portrait kite of himself drawn by Claudio and Claudio took about a dozen special WSIKF winders home with him. Lindsey wrote an article for the AOK newsletter. Anyway, just wanted to let you know there is someone out here who has access to this type of equipment.

knot(tier)ronda

smarties · Joined: 05 Nov 2003 Posts: 493 Location: Dieppe, NB, Canada

CJQ,
Did you had a chance to look at the TL494?

Smarties Razz