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I have a 1.5kW 220VAC 1 Phase dust extractor. It's controlled by what looks like a DOL switch KJD17B/5T (so I assume the 5th terminal is an overload).

KJD17B Datasheet

Wiring diagram on duct collector: From what I can see it's DP/ST and has L/N In and L/N Out and then a 5th connection form the motor which I can only assume is some sort of overload.

I'd like to add a remote start/stop, but it looks like the KJD17B is an enclosed device so I can't wire my remote start/stop in parallel/series.

I'd welcome advice on how to achieve my remote start solution? Should I try to re-wire the DC and bypass the KJD in favour of two external DOL start/stop controllers?

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    \$\begingroup\$ We're missing the image of the wiring diagram and the link to the datasheet. Hit the edit link under your question. \$\endgroup\$
    – Transistor
    Nov 10, 2018 at 11:26
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    \$\begingroup\$ Updated with what I have. \$\endgroup\$
    – Gavin Hill
    Nov 10, 2018 at 11:29

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The fifth connection is under-voltage lock-out - notice the symbol "U<" in the little box on the switch: -

enter image description here

It also tells you on page 1 of the data sheet that there is a feature that prevents restarts should the AC fail. That connection is associated with that feature and, maybe the connection to the motor is because there is an over-temperature contact in the motor that can also trip the magnetic relay internally.

This makes adding a remote start/stop circuit somewhat problematic but, if you are fit for the task, the new start/stop circuit would need to come down stream of the KJD17B and could be the conventional self-latching relay circuit and wouldn't need to be double pole: -

enter image description here

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  • \$\begingroup\$ Thanks Andy. So in your diagram The AC_240V would be the supply from the existing switch? I'd leave the (probable) thermal cutout from the motor in place as that would still cut-out upstream. My remote start/stop would work as long as there wasn't power loss to the existing switch as that would reset it and the AC fail feature would kick in. \$\endgroup\$
    – Gavin Hill
    Nov 10, 2018 at 11:48
  • \$\begingroup\$ Correct interpretation; the KJD has to be upstream so it still provides supervisory protection features and still latches when you press "green". \$\endgroup\$
    – Andy aka
    Nov 10, 2018 at 11:56

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