Will a 180V DC Motor Turn with 60V DC going into it?

[Uncle Fester]

there are brushless dc motors !!! when i was going thru training in 1960s the tutor bought in a lucus dc motor that had a rotor made of a series of bar magnets and field windings on stator unusual in those days but still brushless (and gutless from memory )lol

The field windings would have to be powered by an alternating current or a series of pulses, NOT DC !
Every step motor works like that too. You might be providing a DC but there is some sort of configuration that converts it.

Brushless DC motors all require some kind of external circuit.

[GT250]

Hi Guys,
First I have to aplogise.
I actually did not believe in hinekadon's reply about gluing the magnets. However, I was wrong and my previous post was a tad sarcastic. My apologies to hinekadon.

My last post was misleading and incorrect. I did however, have every intention of telling what really happened, and had no idea that other people would respond about 'gluing'.
The magnets were not loose.

The fault was elsewhere. A very simple fault. Only taking apart the motor would have shown what was wrong.

I include some photo's and the last one (Full Motor Showing) - to the keen eye - will show what was wrong.

Top Off Motor.


Magnets.


Brushes with lots of wear to go.


Opened Motor with fault Showing.


Once again my apologies for being ignorant to hinekadon and others who tried to help on that 'glue' issue.


GT250.

[hinekadon]

so what are you going to do with it /?as it is repairable if you know how ? do you want to know or not ???

[GT250]

The Negative connection had come loose, as in the last pic.
Simply soldered it back on and done!

Obviously a bad solder and I guess the vibration over time did the trick.

[hinekadon]

they are spot welded on manufactuer solders fine

[loopyloo]

Better get rid of the carbon between the poles too, before you end up with a short.
Just scrape it out gently with a fine pointed object.

[tristen]

Good advice from Loopyloo.

We always used a suitably shaped piece of broken hacksaw blade for the purpose of undercutting the insulating material which separates the commutator segments.

We also dressed the commutator (rotor) surface by placing the commutator shaft in the chuck of a pedestal drill, rotating it at slow speed while holding a strip of very fine emery paper against the commutator surface to thoroughly clean and polish it.

(Use a lathe for this purpose if dressing/polishing the commutator from a larger motor to avoid bending the shaft).

Finally, visually inspect the commutator surface after this operation in order to make sure that there are no metal shavings shorting the commutator segments,

Bush type bearings, where possible, were soaked for some hours in warm machine oil in order to lubricate them. (The purpose of warm oil was to ensure that the bearing soaked up the oil as they tend to dry out with prolonged use.

[BCNZ]

The burning on the commutator is typical of what I was seeing with these motors.
The brushes are very soft and arc up easily when the motor has too much load on it.
I don't think the copper on the commutator is particularly good quality either.
The design concept with these machines is OK, but like a lot of china sourced stuff it was let down by cheap componentry.
I found that with the electronic controller units, once I'd been through them and replaced all the problem components with good quality parts, they gave no more trouble.