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Help with Nardini TT 1020E Lathe

shaffin

Aluminum
Joined
Jul 15, 2011
Location
Barrie, Ontario, Canada
Hello,

I just purchased a used Nardini lathe that powered up using 208v/3ph service that I have here at my shop. I encountering ont of the following weird symptom:

1. The motor producing a buzzing sounf as if it tries to run the spindle but cant

2. The lathe trips and burns out one of 3 motor fuse which is a CC Type fuse rated for 12amps

3. The spindle starts rotating but gives up after a couple seconds


I am not an electrician by any means but am trying to make sense of this problem to get the lathe running. I think the issue seems to be that the motor fuses are currently under rated, and probably require larger fuse capacity. I just didnt want to try without some help here and burn the motor out :-(

- I am attaching a picture of the motor plate (2.5hp rated motor)

- I am also attaching picture the fuse rating chart that is attached to the electrical panel door

- I am also attaching a picture of the inside of my electrical panel

I am hoping that someone more knowledgeable can provide some feedback and help.

Thank you.

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Motor starter has electronic overload. This is the main overcurrent protection device. Set it for motor nameplate amps. Check and tighten all electrical connections. Disconnect 3 motor leads at motor. Press start and check voltage at all 3 contactor output terminals phase to phase. From your description you are missing a phase. Check fuses. Does contactor pull in properly? If not check control circuit.
 
- I am attaching a picture of the motor plate (2.5hp rated motor)

Look again.

Plate shows a SINGLE VOLTAGE, (220) but TWO SPEED (870 RPM / 1740 RPM) motor, different HP (1.6 / 2.5) for each RPM rating, FLA current according ( 8.8 / 7.4 A)

There will be more than "three" wires if both speeds are selectable by the operator.

Control switch, relay(s), contactor(s), wiring & terminations for that will be more complicated than single-speed.

More info / more "detective work" is needed.

First possibilty is that your shop may HAVE 208 Wye 3-Phase, but the machine is blameless - all three phases may not be GETTING TO it over the individual branch feed or may be interrupted inside the machine if they ARE making it that far.

Check that starting at the wall, first, then the cabling & plugs/sockets or fixed terminations, then the machine... etc. Takes very little time.

Otherwise, you are more likely to have a control / starter relay or contactor malfunction, a broken lead, damaged termination, etc. than wrong fuses, for example.

Do hope it is not a failed motor winding, but "it could be" such.

Best to keep the fuse values at the OEM recommendation until that has been found and corrected.

Going forward...

You can "learn all this", given time and dedication enough. No harm, positive gain, to understanding your machine better.

It would be faster to get an electrical guru on-site.
One who ALREADY HAS the test gear as well as the skill and experience to isolate the fault. You will still learn - but from his work. I did say "faster?"

Too slow over the internet, one tiny slice of assumption, error, then correction, then counter-correction, then a sliver of new info.. lather, rinse, repeat, one slow step at a time!

:D
 
It sounds like the motor might be single phasing. Check that all connections in the path from the mains to the motor are tight. If there is a 2-speed switch check those connections and check the switch contacts. Check also the contacts in the relays that control the motor.

Btw, there are 2 kinds of electricians: installers and maintenance/troubleshooter. The installer will probably be useless for troubleshooting.
 
It sounds like the motor might be single phasing. Check that all connections in the path from the mains to the motor are tight. If there is a 2-speed switch check those connections and check the switch contacts. Check also the contacts in the relays that control the motor.

Btw, there are 2 kinds of electricians: installers and maintenance/troubleshooter. The installer will probably be useless for troubleshooting.

LOL!

Probably!

OTOH? He can run a NEW branch circuit from a cold start about as fast as the "detective" can get a meter onto an existing one!

Muscle-memory vs actual THINKING?

:D
 








 
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