Change old AC motor to BLDC motor in Sieg C6

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi folks here!

I am looking for a new brushless DC (BLDC) motor with speed control to replace an old 550-watt, single-phase electric motor. There are so many variations of BLDC motors with speed control available on Alibaba that it is difficult for me to determine which one would be suitable. I am looking for an 1100-watt motor with a 14 mm shaft diameter and a shaft length of 20–30 mm. If the shaft diameter is slightly larger than 14 mm, I can machine it down to 14 mm, provided the length is sufficient for attaching the pulley. The price is well within my budget.

Does anyone here have experience installing a BLDC motor from Alibaba on a Sieg C6 lathe?

 

Regards Jens Eirik

 

[John HaineParticipant @johnhaine32865]

Several people have successfully used the Jack sewing machine motors to drive machine tools. A search (try Google Gemini) on this forum should bring up some posts.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Does this brushless motor have dimensions roughly the same as the old 550-watt one—such that I could install it in the same spot without major modifications—and does it have a 14 mm shaft diameter and a length of 25–30 mm?

There isn’t much information in the link, and the speed controller unit lacks a reverse function.

[Jens Eirik Skogstad 1]

On Jens Eirik Skogstad 1 Said:

[…]   and the speed controller unit lacks a reverse function.

You might want to ask these people about that ^^^

Servo-Motor 550 Watt JACK JK-513A

[see feature 3.]

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

… or watch this:

.

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MichaelG.

[Clive FosterParticipant @clivefoster55965]

Deleted.

[HollowpointParticipant @hollowpoint]

Why brushless? Why not 3 phase with a VFD?

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Can you explain how do?

[Robert Atkinson 2Participant @robertatkinson2]

Couple of comments, probably not what you want to hear though. These sewing machine BLDC motor kits do not meet UK / EU safety requirements despite what the sellers say.
You cannot easily machine the shafts on these. disassembling the motor is not recommended. It is hard to get them back together within tolerances without tooling.

 

[Hollowpoint]

On Hollowpoint Said:

Why brushless? Why not 3 phase with a VFD?

Yep, I reckon might be the better solution.

[HuubParticipant @huub]

I have mounted a Lichuan AC servo on my Lathe (C-axis) and have bought a HLTD T3D AC servo for my mill. I prefer the HLTD because it is cheaper and all cables have connectors so it is easier wiring.

I prefer the AC servo above a BLDC motor because a servo can run from 0 RPM to Max RPM. Speed can be controlled by a pot meter, buttons, step/dir or PWM signal and a servo can be run as C-axis so you can use the spindle as dividing head, something I use often.

Mounting a stronger motor is easy. But if the rigidity of the machine can’t handle the extra torque you will not benefit.

Beware, a servo needs to be tuned and that can be more complicated then setting a few parameters on a BLDC driver.

 

 

[Clive SteerParticipant @clivesteer55943]

Robert. In what way do these sewing machine motors and controllers not meet UK/EU safety requirements?

Clive

[Clive Steer]

On Clive Steer Said:

Robert. In what way do these sewing machine motors and controllers not meet UK/EU safety requirements?

Clive

Hi Clive,

Two issues. The first is easily seen in the photos. Th connectors are not suitable for mains voltage when accessible to the user. They use either “molex” or “avionics” style connectors. The molex have retecangular plastic insulation and a flexible rubber “boot” on the back. These are not “touch-proof” i.e. recessed contacts, do not have a make first, break last protective earth contact and don’t have a cable strain relief. The avionic connectors have a round metallic body and screw-locking. The are also used on CB radio microphones. The are not touch proof, don’t have proper earth contacts and the metal shell is not earthed. This is important for both the motor and control connectors as the circuits in these drives are not isolated from the mains.

Second issue is interference. These units don’t meet emissions for residential / domestic use.

Robert.

[Author]

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