Please help me

[canadianhorsepower]

to all electrical geek

I purchase a brand new lathe about six month ago
Craftex CT043 12x36 2hp 220 volts
yesterday night while working on My- Rupnow's engine
I burn the 3rd motor :wall:
doing small parts shutting it off often and restarting after about 10 time
it didn't want to start was howling like a moose and jump the breaker.
twin 40 amps

The big issue here is that the previous lathe a CT089 using the same motor
was plug in the same wall outlet for 2 1/2 year no problem
both breaker were replace after the first motor blew.

when the second motor blew I plugged it in my milling plug outlet
they are side by side

and yesterday the 3rd one blew
any suggestion what to do

 

[stevehuckss396]

Did the motor blow? Does the motor have capacitors on it? If so that is what most likely blew. They are rated for so many starts per hour and can fail. The one on my mill failed in less than a year. I bought good caps not made you know where and they are still in service today.

 

[canadianhorsepower]

Did the motor blow? Does the motor have capacitors on it? If so that is what most likely blew. They are rated for so many starts per hour and can fail. The one on my mill failed in less than a year. I bought good caps not made you know where and they are still in service today.

thanks Steve for your reply;

blown , being from a engine builders really meant it's fried.
the second one I had some work to deliver and went at it with an
extinguisher to cool it own

and started on the spot after that I only use in manual reverse
gears , they are synch it doesn't matter

 

[stevehuckss396]

Well just for future reference, motors can overheat if started too many times in a given time frame. Rule of thumb is 8 to 10 times the full load current of the motor at startup. As the motor starts and gets up to speed that start current reduces. If your machine is in high speed and takes longer to ramp up to speed the motor takes more abuse in the form of heat. Capacitors are the same way and usually fail sooner than the motor. Not always.

 

[canadianhorsepower]

thanks Steve

but this one is dead, even today after almost 24 hr
it still wont start

I think I will push for a replacement ( lathe and all) almost
4g a pieces it should be better then this .........................
don't you think

 

[Entropy455]

A 2 HP motor on a 220 volt line shouldn’t pull more than 10 amperes when fully loaded. If you are connected to a 40 ampere breaker, you are not doing your motor any favors, as it will burn up long before the breaker trips.

The motor should be on a 15 amp or 20 amp breaker at the most.

Things that can make the motor run hot (questions to ask):

Is there excessive running torque on your machine? Are the ways gummed up with cosmoline? Is there a set-screw that needs to be loosened up?

Is the motor getting proper ventilation?

Are you sure that you’re actually connected to a 220 volt source? Attempting to run a 220 volt motor on 110 volts will cause it to pull excessive current, and run very hot - just like you're describing. . . .

 

[canadianhorsepower]

The motor should be on a 15 amp or 20 amp breaker at the most.

Things that can make the motor run hot (questions to ask):

Is there excessive running torque on your machine? Are the ways gummed up with cosmoline? Is there a set-screw that needs to be loosened up?

Is the motor getting proper ventilation?

Are you sure that you’re actually connected to a 220 volt source? Attempting to run a 220 volt motor on 110 volts will cause it to pull excessive current, and run very hot - just like you're describing. . . .

thanks for your input but
come on after the 3rd one on the same circuit and different breaker.


As for temperature since my last cancer fight air-conditioning keeps it
to a cool 60 degree f

 

[Entropy455]

A bad circuit breaker does not normally burn up a motor.

Is your lathe connected to a one-pole breaker (http://images.lowes.com/product/converted/047569/047569062711lg.jpg)
or a two-pole breaker (http://images.lowes.com/product/converted/047569/047569062773lg.jpg)?

Can you identify the plug that your machine is using, from one of the below attached links?

http://www.household-appliances.com/images/ws_159.jpg

http://www.kvm.com.au/images/plugs.jpg

 

[stevehuckss396]

A 2 HP motor on a 220 volt line shouldn’t pull more than 10 amperes when fully loaded. If you are connected to a 40 ampere breaker, you are not doing your motor any favors, as it will burn up long before the breaker trips.

The motor should be on a 15 amp or 20 amp breaker at the most.

Maybe not!

 

[stevehuckss396]

Hay CHP!

If you feel like it get me some info off the motor name plate. (if you can see it). See if you can find some or all of these things.

Full load amps (FLA)
Code Letter ( it will be like E or F)
Service factor
Temperature rise Celcius
Horse power

Entropy455 may be right but lets do some math to see if you meet the national electrical code.

 

[Entropy455]

There are a few assumptions that require clarification:

Is the electric motor properly sized to meet the power requirements of the lathe? I.E. are you running the correct motor as specified by the lathe manufacturer, or something you installed to make it work? Reason – an undersized motor will burn out if it’s overloaded for extended periods of time, with an oversized breaker.

An electric motor getting so hot that you need to cool it with a fire extinguisher, screams of an under-voltage condition, with excessive current - or too small of motor, that's overloaded.

Engineering Notes: a 100 percent efficient 2 HP electric motor, running fully loaded on 220 volts RMS, will pull 6.78 amperes. In the real world (with a typical 70% efficiency) the average 2 HP motor will pull 9.7 amperes when fully loaded, and generate 640 watts of waste heat within the windings. This is about half the thermal output of a typical hairdryer – i.e. it’s not normally enough to burn up a motor. Something else is wrong. . . . .

 

[Draw-Tech]

Hi Canadaianhorsepower

Did you check to see if the motor has hi and low voltage taps? You may be running the motor set for low voltage, and your doubleing the voltage to the motor.

Jack
Draw-Tech

 

[canadianhorsepower]

thanks for all your inputs
Here is the story

they receive my new motor yesterday, they called me to go and pick it up
and I ask them to check it before cause I was going to have a "fit"

they called me back 1 hr later saying " don't worry Luc we wired it checked
it and everything is fine"

Drove down there and because of so many problem with these motors, I told the technician show me that its fine be fore I leave.

dam it didn't reverse

is going on here.
took his multimeter and start doing some testing, needless to say I was steaming.

after a few minutes of testing we realize that the wire ID
were not on the proper wire...... the motor was running on the starter cap and circuit all the time. When I got home check my old one and it's wired the same. The wiring diagram plate is wrong.
I should be installing it today after storing my 3 motorcycle for winter
and hope its the end of this story.

I told the store manager if I have one more issue with this lathe I'm just going to bring it back and get another one

 

[dman]

is there any noise or vibration when the motor runs? many single phase motors have an internal centrifugal switch that kicks out the start winding at rpm. if that's not working the phase shift for the start winding isn't likely to match the angle of the pole of the start winding at full speed and the motor will get hot and make noise... (ask me how i know this) if the motor doesn't have this internal centrifugal switch then you would need a potential relay or a momentary switch and possibly 2 contactors to come up with a circuit to start the thing and drop out the start winding properly.

 

[canadianhorsepower]

Hi dman
I know the starting circuit your talking about and the are common on swimming pool pump because they don't use starting cap

the issue here was the wires were not properly tag from factory and was always running on the starter cap. It simply made things worst being a new lathe and not use to the sound it should do when running.

Now that's is proper wired I had to switch my belt to reduce the RPM
on low speed quite the difference
last Tuesday I work the hell out of it simply trying to destroy it before I put everything back together Max amp pulled 6 amps and temp between 80 and85 degree F

now I keep my finger cross:hDe:

so does the salesmanRof}Rof}

 

[petertha]

the issue here was the wires were not properly tag from factory and was always running on the starter cap. It simply made things worst being a new lathe and not use to the sound it should do when running.

Do you mean wiring issies kind of internal to the motor itself? Or the motor was ok & wiring related to motor related panel circuitry in the lathe?

My friend had a Chinese lathe motor problem sounds almost exactly like yours. Kept cutting out sporadically. Turned out it was wired incorrectly right from the factory. He was checking it against the so called 'factory' electric schematic, but it hilighted several other differences that didnt match, so he didnt know what to trust, the schematic or actual wiring. Eventually he hooked up with a guy that took a picture of his same lathe or somehow made a sketch. Very frustrating. I hope you get it resolved.

 

[canadianhorsepower]

Do you mean wiring issies kind of internal to the motor itself?
Very frustrating. I hope you get it resolved.

Yes the motor internal wirring did not mtach the plate from factory
but it seems to be all fine now and what a difference

 

[Entropy455]

It seems insane to me that a manufacturer would produce a complex machine (with dozens and dozens of moving parts - producing foundry castings, machining the castings, heat-treating parts, complex assembly, etc) – and they apparently don’t have adequate quality controls to properly wire it up.

A simple turn-on & run current check at the factory prior to crating would’ve indicated there was an electrical problem.

I guess we live in an age where a manufacturer only needs to produce a 90% product, and the consumer is responsible for the other 10%. . . . . perhaps 20% - if the product is being shipped overseas.

 

[Johann]

Question,
After I have read this I wonder, will it not be beneficial to the lifespan of a lathe motor (with vfd) to rather start up at min revs, and then to increase the speed to the desired rpm ? Or perhaps set the system to a longer start up cycle, and if so, any suggestions on the timespan from startup to full rpm?

Johann

 

[canadianhorsepower]

A simple turn-on & run current check at the factory prior to crating would’ve indicated there was an electrical problem.

Entropy455 ----------- It's worst then this all foreign when they come
to Canada one of the government engineer open the crate plug the motor
start them up and if everything is OKRof} they put the CSI sticker
for approval :wall::wall:

I guest mine had a quick check