L5 issue

[Neil TaylorParticipant @neiltaylor16781]

Hi all

im sorry to bother everyone but I have a l5 with a three phase motor and a 3 to 1 transformer, when i turn it on the lathe makes a chattering noise and doesn’t stay on for long, does anyone have any advise, I hope this is ok to post here

all the best to you all

[John HaineParticipant @johnhaine32865]

What do you mean by a 3:1 transformer?

[Neil TaylorParticipant @neiltaylor16781]

Hi again

sorry to clarify it’s a Clarke pc60 3 phase converter

regards

[Clive FosterParticipant @clivefoster55965]

Chattering noise followed by stopping is generally due to insufficient voltage on the operating coils of the contactor switching the motor on and off making it unable to stay in the “ON” state.

Best practice is to run the control gear off the 240 volt mains feed. The third, wild or generated, leg is somewhat unstable and doesn’t exist until the more is turning.

Worth verifying that your contactor does have a 240 volt coil.

I presume you have converted the motor internal connection from star (Y) to delta so it will run properly off the 240 volt converter output.

Clive

[Neil Taylor]

On 19 December 2024 at 13:31 Neil Taylor Said:

Hi all

im sorry to bother everyone but I have a l5 with a three phase motor and a 3 to 1 transformer, when i turn it on the lathe makes a chattering noise and doesn’t stay on for long, does anyone have any advise, I hope this is ok to post here

all the best to you all

Hi Neil. Fine to post here.

1. Has the Lathe has run OK on the static convertor for yonks, and then suddenly failed. Or
2. This is a new installation that’s never worked properly?

Case 1 suggests the static converter is sick.  Often due to capacitor failure – they can be replaced.

Case 2 suggests the static converter is unsuitable (maybe too small), or otherwise not a good match to an L5.  I don’t know what an L5 needs and hope a few owners will comment.  Static converters are a bit of an electrical bodge, and don’t play nicely with all machines.

Dave

[Neil TaylorParticipant @neiltaylor16781]

Hi clive

thank you for your reply I will pass this on to my friend who is a sparky regarding what you said

thanks again

[Neil TaylorParticipant @neiltaylor16781]

Hi dave

this is a new setup so I have no older information, thank you for your reply

[Pete RimmerParticipant @peterimmer30576]

Check that the lathe’s control circuit is not fed from the generated phase. what you’re experiencing is a common symptom of that.

[Neil TaylorParticipant @neiltaylor16781]

Hi Pete

I will pass this on thank you for your reply

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