Dc motors wont work on ac of any frequency. Low frequencies used in traction improve the motors' starting torque, and of course this is important.
I've got a very old domestic appliance that claims to handle 25Hz, but where 25Hz was ever found in homes in UK I dont know. I wonder if a few old private gen plants used it at the time, and they thought theyd corner the market, but am far from convinced.
NT
You did not mention what appliance it was that was rated also for
25hz, but all toasters, and radiators would easily be included in the list, and these would also work on the ultimate low frequency (DC).Although 25 Hz was mostly used for trains, a lot of railway housing and stations were also using this frequency (seeing it was readily available). And you could see the flicker in the lighting where 25Hz was used.
Peter Dettmann
Not necessarily true. Clearly they work on ZF, and would continue to work until the motor impedance became significant.
Actually, it was 25 Hz and it was used in areas around mines.
Well, that depends on the type of DC motor, doesn't it?
There are motors that work just fine on either AC or DC.
Here's an article that agrees with what I said:
then they arent dc motors. Not often one has to state something quite that obvious.
NT
yes
no. A dc motor is by definition one that runs on dc only. Typically these are permanent magnet motors, in which direction of rotation depends on polarity. Motor impedance is not the issue. Motor impedance is the issue with universal or ac/dc motors.
NT
Not quite true. Series wound DC motors (often called "universal" motors) work on AC and DC. Frequency is a don't care. Often used in cheap appliances, like mixers or hair dryers.
Steve.
Engine starters are also frequently of this type. Perhaps less now with permanent magnet gear starters.
Thomas
Nope. I doubt anyone has EVER built a traction motor with permanent magnets.
And yet they are called AC/DC motors. And run on either. Seems you need to take a course - or two - before correcting others.
Still trolling? Sci.electronics.design not big enough for all your nonsense? What transformers are you talking about? Those cheap, imported Chinese wall warts, or pole pigs? Just about everything else is built with a SMPS. Why waste both iron and copper to build 50 Hz transformers for the domestic market?
You just can't wait to get in another of your anti America digs, can you?
precisely, not dc motors.
NT
How do you think they control the frequency? They adjust the water flow through the turbines to get the required speed. They have to match the speed and phase of the grid before they can connect, then they increase the water flow till the generator is producing the desired current.
It would be very easy to change the speed, but it would make more sense to use an alternator designed for the desired frequency.
... which one would then need to run at the correct speed.
And it is (or was) the practice to run an AC clock off the output and trim the speed to keep it at the correct time using another reference. That way all of the AC clocks in town would stay in time.
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