[JFettig]

My surplus motor has been acting funny ever cince I got it to push out near 8000rpm. Finally it bit the dust, I was miling today, It started out at 5000rpm, and kept dropping slowly untill it hit like 3800rpm and smoke was billowing out of it(I have a fan blowing down on it through a shroud, comming out of there)

I am thinking about just buying another and not pushing it to its limit resulting in screwing it up, but is there a better motor I can get, that 1) wont break my wallet, and 2) hopefully run with the controller I have(8 amp 130vdc controller from surplus center)

I know JR has the same motor and runs his full blast but he has a bigger controller. I would like to get something that works well.

Jon

[JFettig]

The motors I am looking at currently are:
http://www.surpluscenter.com/item.as...tname=electric
and
http://www.surpluscenter.com/item.as...tname=electric
this second one doesnt have contin duty, so its still the first one, the first one is the one I have currently. I would like something a little higher quality.

Jon

[JRoque]

I would like something a little higher quality.

Yeah me too. At $20, I just got me 2 of them. How hot did it get? I think they're rated to 220F but I keep mine at less that 130F. I have an alarm set at 160F to avoid overheating.

I've been camping on eBay for months now waiting for a motor that's 1. not too heavy/big, 2. <180V 3. Fast! Everyone and their brother makes <3600 RPM motors but not faster. If nothing shows up soon I might sacrifice my PC router and see if I can mount it on better bearings that wont get so hot. The PC router is loud though. I don't know if I can deal with that again. The El Cheapo motor I run now is soooo quiet.

JR

[JFettig]

JR, I just bought one to replace mine, I was getting a loud wine, from my v-belts, I now have a GT2 timing belt/pullies setup comming that I have to adapt to the motor and spindle which shoudl run much quieter.

My motor was very hot when it finally went, but before then I had an 80mm fan on it keeping it cool but it just didnt handle it this time, heres a few pictures of a melted mess:


Jon

[ynneb]

Surplus motor went POOF

Has it turned homosexual?

[Halfnutz]

From what I understand by talking to the tech at surplus center is that the problem most of the time with these setups is the current rating of the controller and the current draw of the motor. In other words he said that most of the problems he hears about is with the high current motors and suggested to me to find one with a low current rating. Also high current = higher heat, usually for itermitant use wearase lower current motors can run for longer periods. I have a 230volt 5amp motor I run withthe Minarik but not at the speeds you get. Actually without a tach I dont even know what RPM i am running. How do you measure your RPM?

[MIKE JEFFERS]

hey ynneb do you know that if you spell your name the other way round
it spells benny?

there's always one.

[MIKE JEFFERS]

jon
what sort of spindle are you driving with that motor?
mike

[JFettig]

Halfnuts, the motor is rated at 18amps and I am only giving it 8 at the most.
Mike, I am driving my X2 mini mill spindle with new bearings in it(withstand up to 10k rpm)

Benny..........



Jon

[Bloy2004]

My surplus motor has been acting funny ever cince I got it to push out near 8000rpm. ......

Jon

Jon, How did you get it to 8000rpm. more than 180VDC?

Bloy

[JFettig]

Its a 130vdc motor, theres a little pot on the controller where you can controll the top speed which allowed me to get a higher rpm.

Jon

[Bloy2004]

oh yah.....130Vdc... it's early and still rubbing my eyes...
Does that pot allow more than the max 130VDC into the motor? and if so, what voltage was the motor receiving?
...just wondering how FAR over 130Vdc the motor was.....to get the 8000

[Al_The_Man]

It is very rare to see a brushed motor that will run safely or is rated over 3000rpm.
Al.

[ViperTX]

JFettig....can't tell....but it looks like the bearings overheated and that seems to have caused your problems....jpg is not clear.

[JRoque]

Hey Al, did you really mean brushed motors? All common wood routers are universal motors and they do ~20K RPM.

Cheers,
JR

[JFettig]

ViperTX, the bearings were just fine, the plastic melted around the brushes.

Jon

[Al_The_Man]

Hey Al, did you really mean brushed motors? All common wood routers are universal motors and they do ~20K RPM.
JR

Yeah, sorry, I had servo motors in my mind for some reason.
Time for a coffee break
Al.

[JFettig]

I am looking at picking up this one servo, 7000rpm,45 lb-in,
In mach2/3 it has the spindle output, PWM and step and direction outputs, Using the step and direction outputs, can you hook up a drive like a gecko drive and have it power a servo? even do stuff like rigid tapping?
-edit- I dont know if it is brushed or brushless...

Jon

[Mariss Freimanis]

What may have happened is you exceeded the arc-over speed for the motor. Brushes arc, the faster you go, the longer the arc tail is from the brushes. Once the arc extends to 180 degrees it reaches the opposite brush. At that point it's all over for the motor. The arc is now sustained and quickly burns up the motor. Smoke, fire, disaster all around!

Mariss

[Halfnutz]

So, I still dont see how you can tell what the RPM actually is unless you have a strobe tach or some type of tach. Thats a great idea, changing the bearings and motor, I have a little X2 also, I might try the same thing.