Jack jk 513a

This topic has 15 replies, 7 voices, and was last updated 1 January 2026 at 09:31 by Nev Whitehurst.

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31 December 2025 at 10:11 #830609
Nev Whitehurst
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@nevwhitehurst53938
Hi . Has anyone fitted a speed control switch to a jack jk 513a motor / control box ? If so can you tell me how to go about it please . The switch I have has a live and neutral too the motor and live and neutral from the motor , I am not sure if it can be done on a jk513a because you can preset the speed via the control panel . I don’t have a foot control and I would prefer to use the speed controller on it , I will appreciate any advise any one can offer me on this subject . Thank you
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31 December 2025 at 11:04 #830630
noel shelley
Participant
@noelshelley55608
Hi Nev, a quick look on google shows some information that may help you and I would think it should not be to difficult to convert the foot pedal to a control panel type either by using the existing parts or it may simply be a case of using the right pot to effect speed control. Noel.
31 December 2025 at 11:17 #830635
Nev Whitehurst
Participant
@nevwhitehurst53938
<p style=”text-align: left;”>Thank you Noel . I will have a look , I have been trying to find information on google but it keeps saying refer to the manufacturer manual. Will take another look now cheers</p>
31 December 2025 at 13:05 #830659
Martin of Wick
Participant
@martinofwick
Perhaps you need to send us a photo of what your 513 consists of.

Normally they have a motor, a large box of control electronics, with some serious voltages inside and a small box with a movable grey or silver lever poking out, which is the speed controller. All the required connecters are provided and it is a stand alone unit. Plug everything in, turn on, twiddle said lever and it should all work.

If for some reason you do not have the speed controller box and attempt to run, then the control box should fault to a safe condition and no current will be supplied to the motor.
31 December 2025 at 13:29 #830668
Michael Gilligan
Participant
@michaelgilligan61133
This may be of interest:

.

.

MichaelG.

.

Edit: __ and the manufacturer’s leaflet:

https://www.jack-sewing.com/wp-content/leaflets/MOTORE.pdf
31 December 2025 at 13:39 #830670
Martin of Wick
Participant
@martinofwick
Can never seem to post links any more, but failing that go to the konsew UK site and navigate by brands for 513 motor, you should find the ‘manual’ available as a PDF there FWIW! good luck with that. Not sure how to post a pdf otherwise I would stick it on the site. The version from konsew is actually what passes for a technical manual these days, marginally more helpful than Michael’s.

BTW, the video shows how to set default speeds limits, max and min. The actual speed controller is somewhere at the end of all the various linkages, out of site.
31 December 2025 at 13:50 #830672
Michael Gilligan
Participant
@michaelgilligan61133
Thanks for your useful find of the manual, Martin

Permit me : https://konsew.co.uk/index.php?route=account/download/download&download_id=87

MichaelG.

.

P.S. __ if you wish to post a copy of the PDF just put it in your Documents ‘Gallery’
31 December 2025 at 13:56 #830675
Nev Whitehurst
Participant
@nevwhitehurst53938
Hi Michael . Thank you for the video I have seen them all and I’ve downloaded the manufacturer manual for it too . Thanks for your help
31 December 2025 at 13:58 #830676
Ian P
Participant
@ianp
I know I’m banging on about this again but anyone contemplating using one of these sewing machine motors should be made aware that the wiring (even to the Hall effect speed control device) is,

DIRECTLY CONNECTED TO THE MAINS SUPPLY

I am just in the process of using a ‘Jack’ motor on a small milling machine and may replace the Hall device with a potentiometer but I will install it in a grounded metal enclosure.

These motors have excellent performance but I’m not convinced they comply with UK electrical safety requirements even when used on industrial sewing machines.

If in doubt please seek advice

Best Wishes for 2026

Ian P
31 December 2025 at 13:59 #830678
Robert Atkinson 2
Participant
@robertatkinson2
Firstly I must say that I don’t think that these motors comply with UK / EU safety and EMC regulations.
The best “manual” I can find is here https://www.trojansewing.co.uk/wp-content/uploads/2025/05/Jack-Jk-513a-Servo-Motor-Manual-.pdf

You should have either a foot pedal or “speed governer” (a box with lever input). This connects to the 6 pin connector on the main unit. This connector has pins marked “speed” “5V” and “Gnd”. This indicates that the speed control signal is 0 to 5V and could be provied by a simple potentiometer.
If you want a speed control “knob” a simple linear potentiometer will do the job. The value is not critical, 1k (1000 ohms, 4.7k, 5k or 10k would work.
A concern is that we do not know if the control circuit has adequate isolation from the mains circuitry including if there is a fault. To ensure it is safe the user should not be able to touch any metallic part of the potentiometer. Ideally use a potentiometer with a plastic shaft and use a plastic knob the covers the mounting nut. It has to be enclosed in a box. Plastic is ideal but if it is on a metal panel a mains earth MUST be connected to the metalwork.
The counter-clockwise end of the pot connects to the GND pin, The wiper connects to the SPEED pin and the clockwise end connects to the 5V pin.

IF you do not feel confident wiring this safely please get help.

Robert.

Robert.
31 December 2025 at 14:14 #830680
Nev Whitehurst
Participant
@nevwhitehurst53938
On 31 December 2025 at 13:58 Ian P Said:

I know I’m banging on about this again but anyone contemplating using one of these sewing machine motors should be made aware that the wiring (even to the Hall effect speed control device) is,

DIRECTLY CONNECTED TO THE MAINS SUPPLY

I am just in the process of using a ‘Jack’ motor on a small milling machine and may replace the Hall device with a potentiometer but I will install it in a grounded metal enclosure.

These motors have excellent performance but I’m not convinced they comply with UK electrical safety requirements even when used on industrial sewing machines.

If in doubt please seek advice

Best Wishes for 2026

Ian P

Hi Ian . I have decided to use a lever from the arm of the square box as I can use it on 3 settings I can make some more slots so I can run it on various speeds if I need too . I know the circuit board still holds the power at least 2 minutes after turning off it takes around 30 seconds once you’ve turned it off for the display to go out and it still holds power at least 2 minutes after that so it is not something you can mess about with too much unless you know what you are doing . Thanks for the advice
31 December 2025 at 14:22 #830683
Nev Whitehurst
Participant
@nevwhitehurst53938
On 31 December 2025 at 13:59 Robert Atkinson 2 Said:

Firstly I must say that I don’t think that these motors comply with UK / EU safety and EMC regulations.
The best “manual” I can find is here https://www.trojansewing.co.uk/wp-content/uploads/2025/05/Jack-Jk-513a-Servo-Motor-Manual-.pdf

You should have either a foot pedal or “speed governer” (a box with lever input). This connects to the 6 pin connector on the main unit. This connector has pins marked “speed” “5V” and “Gnd”. This indicates that the speed control signal is 0 to 5V and could be provied by a simple potentiometer.
If you want a speed control “knob” a simple linear potentiometer will do the job. The value is not critical, 1k (1000 ohms, 4.7k, 5k or 10k would work.
A concern is that we do not know if the control circuit has adequate isolation from the mains circuitry including if there is a fault. To ensure it is safe the user should not be able to touch any metallic part of the potentiometer. Ideally use a potentiometer with a plastic shaft and use a plastic knob the covers the mounting nut. It has to be enclosed in a box. Plastic is ideal but if it is on a metal panel a mains earth MUST be connected to the metalwork.
The counter-clockwise end of the pot connects to the GND pin, The wiper connects to the SPEED pin and the clockwise end connects to the 5V pin.

IF you do not feel confident wiring this safely please get help.

Robert.

Robert.

Hi Robert . I have decided to use it as it is but using a lever from the arm which I can change the speed as I wish . I’m normally ok with electrics but the wiring on this has got me scratching my head , plus the power it holds after being turned off is worrying too . So I’m going to leave it be now and use it as it is set up now . Thanks for your advise
31 December 2025 at 14:23 #830684
John Haine
Participant
@johnhaine32865
Just for some perspective, I use a KB Electronics speed control to drive the DC spindle motor on my little mill. This is a thyristor type controller (motor is commutator type not brushless) with all the circuitry floating at mains volts. Speed is controlled by a 10k linear pot supplied with 10V from the unit inside the manufacturer’s metal enclosure which is grounded but the electronics is NOT connected to the box. As Robert says, the pot has a plastic shaft and the knob is insulated. All works well and quite safe, and easy to emulate if you need to.
31 December 2025 at 14:38 #830689
Nev Whitehurst
Participant
@nevwhitehurst53938
Hi John . Thanks for your advise but I’ve decided to leave it as it is apart from a lever I made up to give me different options of speed . I’m a bit puzzled with this one I’m normally quite confident with things like this but this has left me scratching my head. It’s usable as it is which is the main thing and it is quite a powerful motor so ideal for what I need . Thanks again
1 January 2026 at 09:04 #830731
John Haine
Participant
@johnhaine32865
Nev, sounds like a good plan. I was just making the point that live chassis systems can be made perfectly safe. After all, virtually all crt tvs were made like that until switch mode power supplies became cheap enough, to save the weight and cost of the mains transformer that would otherwise have been needed.
1 January 2026 at 09:31 #830733
Nev Whitehurst
Participant
@nevwhitehurst53938
On 1 January 2026 at 09:04 John Haine Said:

Nev, sounds like a good plan. I was just making the point that live chassis systems can be made perfectly safe. After all, virtually all crt tvs were made like that until switch mode power supplies became cheap enough, to save the weight and cost of the mains transformer that would otherwise have been needed.

That’s the way things are being made nowadays to stop people from playing around with things , you just have to look at cars nowadays , back in the 1980s I took the engine out of my mk1 escort took it to the shed stripped it fixed it rebuilt it and put it back in the car nowadays it will take you a day to get too the engine . They are making things that you will end up taking to the dealers . Well it does what it’s meant to and I can tinker around and see if I can come up with a better idea than the one I’ve got . Thanks again John and a happy new year to you
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