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-   -   Wiring a 110V two-phase motor? (https://www.vintage-radio.net/forum/showthread.php?t=172154)

Uncle Bulgaria 17th Oct 2020 11:32 am

Wiring a 110V two-phase motor?
 
3 Attachment(s)
My brother just brought round this motor and I don't know how to wire it up. The reds and blacks appear separate from one another, with red-red and black-black having 300k resistance on my DMM.

EDIT: 300R. See below.

barrymagrec 17th Oct 2020 11:36 am

Re: Wiring a 110V two-phase motor?
 
300k sounds a bit open circuit for a motor winding.

I would expect a cap to be involved but the motor plate would normally give a value.

Uncle Bulgaria 17th Oct 2020 11:38 am

Re: Wiring a 110V two-phase motor?
 
That's what I thought, but since both are the same I wondered if there was something else in the casing, or the inductance was upsetting the reading.

EDIT: my error. I've just done it again and both are 300R! I misread the display, which was 0.370k...

barrymagrec 17th Oct 2020 11:41 am

Re: Wiring a 110V two-phase motor?
 
Easily done.

Perhaps it expects an actual 2 phase supply :- https://en.wikipedia.org/wiki/Two-phase_electric_power

Uncle Bulgaria 17th Oct 2020 11:44 am

Re: Wiring a 110V two-phase motor?
 
I wondered that, but it doesn't look old enough to be genuine two phase. Do you think a capacitor is sufficient to create the phase shift? I suppose I was expecting it to say 'single phase' if it were to be run off normal AC, even with a capacitor. However, there's no difference in resistance to imply a start and run winding. Could I damage it hooking up a capacitor in series with one mains leg and one colour, putting one red to one black and the other mains to the remaining colour?

barrymagrec 17th Oct 2020 12:01 pm

Re: Wiring a 110V two-phase motor?
 
I think I`d be inclined to put 110 volts across one winding and feed the other via a cap, say 3 or 4uf to start with.

Its a geared motor, can you turn the shaft - if so you may be able to start it by applying power to one winding and giving it a twist.

I think Klaxon were an American company so that could explain the two phase.

duncanlowe 17th Oct 2020 12:08 pm

Re: Wiring a 110V two-phase motor?
 
Quote:

Originally Posted by barrymagrec (Post 1300470)

I think Klaxon were an American company so that could explain the two phase.

Possibly, but the address is Warwick Rd, Tyseley, Birmingham.

ValvoStef 17th Oct 2020 12:15 pm

Re: Wiring a 110V two-phase motor?
 
Try and connect both windings in series, would be very unusual to have a British made 110V two phase

barrymagrec 17th Oct 2020 12:25 pm

Re: Wiring a 110V two-phase motor?
 
The motor plate quite clearly states 110 volts 50 cycles, it was presumably intended for some special application.

Bookman 17th Oct 2020 12:58 pm

Re: Wiring a 110V two-phase motor?
 
Would there be any point in testing this item? After all, lets not forget that it would be reliant upon a suitable supply for it to function.

For information purposes however there a system of simplifying small industrial application transformers that function in open delta format. In this the transformer consists of a three phase primary but only two phases are used on the secondary that are configured vectorally 120 degrees apart. They would then be connected in series with the opposite ends used for measurement purposes; hence the reference to open delta.
These same transformers are also used typically in industrial motor control centres for small power and metering requirements. Where, if I recall the secondary windings would be rated 110V divided by root three which imply the ability to test the item but by using two step up transformers; one for each winding.
Does anyone else concur?
Joe

Uncle Bulgaria 17th Oct 2020 2:40 pm

Re: Wiring a 110V two-phase motor?
 
Some interesting ideas here. I look forward to someone concurring or refuting Bookman's hypothesis.

The motor[s] (I think there may be more) are some my brother has from our grandfather. He's interested to see if they work so he knows whether they're junk or not. Perhaps there will be a use for them subsequently, but as I have the variac he was more comfortable with me looking over them. I know no more than that, but I'd be glad to get it turning.

Radio Wrangler 17th Oct 2020 2:58 pm

Re: Wiring a 110V two-phase motor?
 
Homes an d light commercial premises in the US get a "110-0-110" supply. Cookers get connected across the full thing and see 220v in reality this may be more like 120-0-120 =240 but it still gets called one-ten and two-twenty.

So the centre tapped supply is two lines of 110, but in opposite phase. Can be called two-phase. Two phase means the phases are 360/2 degrees =180 degrees different. No capacitors needed!

America distributes 110-0-110 services as secondaries on the three phase transformer so you could say they have six phase distribution with each line 110 with respect to ground.

For that Klaxon motor, you have to decide whether it's for 55-0-55 meaning 110v total and two phases Or 110-0-110 it isn't clear from what's on the plate.

David

Dave Moll 17th Oct 2020 4:20 pm

Re: Wiring a 110V two-phase motor?
 
Although no expert on these sort of things, I would go along with the 180 phase angle. Two phases at 120 would seem rather unbalanced withn the third phase missing.

Radio Wrangler 17th Oct 2020 4:54 pm

Re: Wiring a 110V two-phase motor?
 
I'm thinking of a bicycle with the two pedals not 180 degrees opposite :-)

David

Dave Moll 17th Oct 2020 5:10 pm

Re: Wiring a 110V two-phase motor?
 
Yes, that's not a bad simile. Bicycle pedals at 120 apart would be difficult to use.

merlinmaxwell 17th Oct 2020 5:10 pm

Re: Wiring a 110V two-phase motor?
 
180 degree phase shift isn't much good to make a motor turn, I guess it has to have a capacitor in one leg.

cmjones01 17th Oct 2020 7:28 pm

Re: Wiring a 110V two-phase motor?
 
Since it's "Klaxon" branded and rotates at 100rpm, I wonder if it was intended to operate the shutters on a pulsed 'nee-naw' type siren? If so, it may have been powered from two of the three phases feeding the blower motor, maybe via a transformer or even taps on the blower's windings. For such a light duty, the extra cost of a winding for the third phase probably wasn't justified.

I think a 180 degree phase difference is unlikely. It's pretty hard to get anything to rotate with two phases 180 degrees apart (do the trig). You need a quadrature component. The standard 120 degrees is fine.

You might be able to get the motor to run using a step down transformer (even less than 110V should be OK for testing) and connecting one winding straight to the supply and the other via a capacitor or inductor to create some phase shift.

Chris

MotorBikeLes 17th Oct 2020 8:05 pm

Re: Wiring a 110V two-phase motor?
 
I know it says 100 rpm, but were not two phase motors not used for positioning? -- thinks, was that 90 degree motors? Maybe I should just go quietly.
I just vaguely recall two phases used in process control for positiooning "back in the days".
Les.

Uncle Bulgaria 17th Oct 2020 8:09 pm

Re: Wiring a 110V two-phase motor?
 
Hmmm. Some interesting theories! I can see the difficulty with a 180 degree phase shift if the thing has to rotate. I've briefly applied ~110V in various configurations with no result, neither rotational nor concerning. A capacitor appears the next step. Could I parallel some 0.47F X-types just to see if it turns, as I haven't any F level film caps? I've eased the rear bearing as it was very stiff to turn by hand.

Would this be live - winding A - winding A1 - capacitor - winding B - winding B1 - neutral? A series connection with the capacitor between the two windings?

broadgage 17th Oct 2020 8:31 pm

Re: Wiring a 110V two-phase motor?
 
I suspect that this might be expecting a true two phase supply with a 90 degree phase angle between phases. Possibly the red pair to one phase and the black pair to the other phase.
In that case there should be a low resistance between the two red wires and a similar low resistance between the two black wires. Between red and black should be open circuit.

Two phase was never popular in the UK and is now believed to be extinct.
Still exists in the USA, but rare and becoming rarer. Most utilities wont supply 2 phase these days, except to existing customers already so served.

Present day USA mains supplies are usually 240 volts, with an earthed center tap to gibe 120 volts for lighting and small appliances and 240 volts for heavy loads.
Some are two phases and neutral derived from a 4 wire 3 phase system, these give the same 120 volts for lighting and small appliances but with 208 volts for heavy loads rather than 240.
In common parlance in America "two twenty volts" often means a supply that is either 208 or 240 volts but the person speaking does not know or care which. May also refer to an appliance intended to work from either 208 or 240 volts as in "I need to buy a two twenty volt stove"

Neither of the above is a proper substitute for a true two phase supply.

Single phase to true 2 phase converters used to exist, but I doubt that you will find one these days.


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