Precision Matthews 1340T lathe motor noise

[jtg]

Hello everyone,
I purchased a new precision matthews 1340t lathe (the Harrison M300 copy) at the end of last year.
I have only put about 5 hours on this lathe due to various other non related circumstances but now to my problem.
I noticed a very loud noise coming from the motor. I will have to get to the back of the lathe to give the specs for motor but it is 220v 3 phase by Cema with ISO9001 certification if that means anything.
I tried calling Matt at Precision Matthews but he would not help. This lathe is new and I thought had a 2 year warranty. So much for that.
I will try to post a pic of lathe and motor but I have never posted a picture online before so be patient.
thanks,
John

 

[precisionworks]

220v 3 phase

Did you mean to say 220v 3 hp, single phase ?

Only two things that go bad on a single phase motor ... the starting capacitor or the centrifugal switch. They aren't hard to work on, but any motor shop can repair it for you if you'd rather go that way. Should be under $50 for either the cap or the switch.

 

[jtg]

I am sorry i meant to say 220v 3 horse 3 phase motor. I use a 10 horse american rotary convertor to run it.
John

 

[cmacclel]

Wow.....what did Matt say?

Mac

 

[wquiles]

Wow.....what did Matt say?

Mac

I was wondering the same thing. In my experience he goes out of his way to help make things right.

Will

 

[precisionworks]

3 horse 3 phase motor. I use a 10 horse american rotary convertor to run it.

That makes sense, as a 10hp rotary is the correct size for a 3hp gear head lathe.

a very loud noise coming from the motor

Sounds like a wiring or control issue, not a motor problem. 3ph motors have no start caps, no run caps, and no centrifugal switch. Rotor, stator, bearings, nothing else, so they either run or they don't. It almost sounds like the motor is being powered by 2 of the 3 phases from the rotary, or that the connection at the lathe is incorrect.

Your wiring should look exactly like the diagram above. L1 & L2 single phase lines go to T1 & T3 on the motor ... the problem is that sometimes people connect T3 (the manufactured phase) to control wiring of the machine. T3 can never be used for control wiring.

Look at the wiring from the rotary to the lathe, especially where the three wires connect to the wiring block at the magnetic starter. If I had to guess, you'll need to swap T1 & T3, or you'll need to swap T2 & T3.

You may want to run that by Jay Yuergens at American Rotary, as he has more knowledge than anyone I know on RPC's.

 

[jtg]

The lathe ran perfectly for months. I have less than 6 total hours on the machine and no noise, then all of a sudden i start it one morning and the clicking noise. I removed the cover to see if the fan blade was hitting something but it was not. I even removed the blade installed with a set screw and slipped it back on to check for wobble and nothing.
You might have something there about the wiring though. Maybe a wire connection under the headstock where the rotary 3 phase comes in to connect to the lathe has come loose. I will check that out.
I did notice when the lathe was delivered new and i removed the plastic wrap I opened the electrical panel door that houses the electrics and that metal plate that everything bolts to was just hanging loose and flopping.
I installed a new screw and mounted it securely then connected the 3 phase wiring and it started up.
I will check all wiring today and let you know.
As to Matt, He has been very nice but when I mentioned a possible warranty issue with the motor the e-mails stopped.
thank you all very much for this help,
John

 

[mototraxtech]

has this been recently(I mean with matt) I emailed him about a week ago and he has not gotten back with me. SO he my be out of town or on Vacation as he has ALWAYS gotten back to me other wise. Also try and call he as I always find it easier to discuss things in person especially when I have a problem.

 

[Atlascycle]

Following Barry's lead, start the converter and check for power across all three of the L terminals on the main motor starter. Check L1 to L2, L2 to L3 and L1 to L3 you should read very close to the same voltage across any combination.


Jason

 

[jtg]

Jason, I will check than right now and let you know
thanks,
John

 

[precisionworks]

that metal plate that everything bolts to was just hanging loose and flopping.

Your either running on only 2 of the 3 phases, or the wiring to one of the control contactors is loose.

Chances are 99.9% that the problem is something other than the motor.

 

[cmacclel]

Your either running on only 2 of the 3 phases, or the wiring to one of the control contactors is loose.

Chances are 99.9% that the problem is something other than the motor.

I thought a 3 phase motor would not even start up on 2 phases.

Mac

 

[jtg]

Jason, I checked the voltage from L1 to L2, L2 to L3 and L1 to L3 and they all read 249 going into the machine.
It is very hard to get to the back or side of my lathe due to a wall and drill press but there is a cover on the top of the lathe motor that I may be able to remove is that where I should check or is it where L1, L2 and L3 are connected to the lathe wiring box.
john

 

[PEU]

has this been recently(I mean with matt) I emailed him about a week ago and he has not gotten back with me. SO he my be out of town or on Vacation as he has ALWAYS gotten back to me other wise. Also try and call he as I always find it easier to discuss things in person especially when I have a problem.

Maybe he is attending IMTS in Chicago, I guess most of the machining industry attend the show.


Pablo

 

[65535]

I thought a 3 phase motor would not even start up on 2 phases.

Mac

It'll run on 1 phase up to 3 phase. It can start on 2 phases.

It wouldn't run well. Not at all.

 

[Mirage_Man]

Have you tried calling Matt (412-787-2876)? I find a quick phone is always better than 3 weeks of emails anyway. I bet he is out of town if he has not responded to emails. In my experience he is one of the most trustworthy businessmen I've ever known. If there is a problem with your machine I have no doubts that he will take care of it.

 

[precisionworks]

I checked the voltage from L1 to L2, L2 to L3 and L1 to L3 and they all read 249

Were those voltage reading taken with the lathe motor running under full load, with the lathe motor running under no load, or with the lathe motor not running? The L1-L2, L2-L3 and L1-L3 voltage readings are only useful when taken with the lathe motor running under full load ... partial load or no load readings are of no value.

From what you've said so far, it appears that both the RPC & the lathe motor are OK. Move the lathe away from the wall a foot or two so you have access to the control wiring box. Open it up and swap T1 & T3, then power up the machine & see if the noise is still there ... no noise means you've found the problem. Otherwise, swap T2 & T3, power up the machine & see if that solves the problem.

If the noise continues after swapping those leads, check for a bad control transformer, or a bad coil on the mag starter, or a loose or bad connection somewhere on the control board, or a bad connection in the motor junction box.

 

[jtg]

Precision works,
what i do not understand is that the motor has always worked fine.
Why would I swap wires? Matt actually helped me when i first bought the lathe to connnect the wires and it worked fine.
It just all of a sudden started doing this months later after about 3 to 5 hours of total usage on the lathe from crate to now.
What you said about checking with the lathe running I did not do. I just checked the live power going to lathe but did not turn lathe on and got about 249 across the 3 lead combinations.
thank you all very much
Hi Brian,
No, i have not tried calling him because we had this e-mail conversation going on until I mentioned a possible warranty problem and then he just stopped communicating and I left it at that. He has always been there in the past if I had a question though. Remember when we discovered the lathes did not have the oil drain holes installed to change the oil. He helped work around that problem.

 

[precisionworks]

Why would I swap wires?

No particular reason ... this may be a better sequence of events:

check for a bad control transformer,

or a bad coil on the mag starter,

or a loose or bad connection somewhere on the control board,

or a bad connection in the motor junction box.

If all those check out, then try swapping the wires.

Three phase motors, being among the most simple motor ever made, either run or they don't run. No middle ground where they sort of run & make noise unless one or both bearings have gone bad, which is unlikely. If a field winding coil burns up, you'll smell it & the motor will not run. If the rotor has one loose bar, that could be the problem but the sound will wake the dead - again unlikely. You can disconnect all 9 motor leads from the RPC & measure resistance from each lead to the motor frame to see if one has grounded out.

If all that's OK, start the motor with the RPC as you normally would, and take an amp reading on each of the three leads (phases). With no load, you'll only have amp draw in T1 & T2, so put something in the chuck that will take at least a minute to cut, set the machine for a maximum depth of cut & max feed & start cutting - your T3 amp draw should be no more than 10% different than the amp draw reading of T1 & T2. The amp reading should be close to the FLA spec on the nameplate, roughly 10 amps.

If you have access to an optical tach or a mechanical tach, check no load shaft rpm, which should be about 103% of nameplate rpm. Nameplate rpm is measured under full load & the motor will turn about 3% faster with no load.

Even though you think the motor is the problem, it could just as easily be a loose sheave (not unusual for a set screw or two to back out), a loose motor mounting bolt that's allowed the motor to move so the belts are no longer aligned, a transmission gear that's moved, etc.

 

[jtg]

Wow,
it sounds like I have my work cut out for me.
I will try and check all of those but it will take a while and get back with you.
thanks,
John