Garden Mini-Chipper/Shredder Replacement Switch Featured

Looks like the switch is either DP make only or SP changeover Don't connect anything

I can't find a datasheet to confirm where the 5th terminal goes, but I am sure that it is for undervoltage sensing - so on loss of power or being unplugged, the switch trips to off, preventing accidental re-start when power is restored.

Is there anything currently connected to that small spade?

From the schematic, it looks as if it is a contactor or latching relay to stop it restarting automatically after a power outage. I would have thought that the sort of switch fitted to table saws - with red and green momentory buttons, such as

- would be a suitable replacement.

With 4 terminal NVR switches they normally have the solenoid that latches the switch "on" connected to the L & N output terminals. So when you push it closed with the "on" button, the solenoid is powered and it stays latched until either the contacts are forced open by the "off" button, or a power interruption cuts power to the solenoid.

My understanding is (but note I don't have one here to test[1]) that the

The intention is that this connection can then be wired through one or more latching push to break switches that act as remote "emergency off" buttons. You can have many such switches, and they all need to be in their "closed" (i.e. not pushed) state to allow volts back to A1.

On a resistance range measure between L & N out. You should see no connection (infinite resistance) between them with "on" button in wither state (i.e. not pushed AND pushed and held).

Then test between N & A1. Again the button not pushed they should not be connected. However with the "on" button held down, you should be able to measure the coil resistance on the multimeter.

Both those functions are provided by the solenoid... it is powered when the non latching "on" switch is pushed. The power be disconnected, or the voltage fall, the solenoid will release, turning off the device.

(the extra terminal has the L side of the solenoid connected, so it can be powered via external stop switches rather than automatically by the L out terminal)

It appears to be a "brake function", throwing a short across the load to actively slow a motor load.

Yes.

You are right. Safety feature to stop the motor.

I don't believe that, as it would not need a terminal to do that.

As I said, it seems to be a terminal that is part of a single pole changeover switch. So the switch can be used in different contexts. That is not uncommon.

What?

If it is a brake, it doesn't need a terminal.

Anyway use of a continuity meter would determine instantly what its logic was, so why not just test it?

YouTube videos suggest that A1 is one side of the latching coil, and it should be looped to pin 4 (assuming you have neutral on input pin 3 and live on input pin 1 that's a link to neutral), either directly or via other interlocks.

nib

Thanks - that appears to be the case.

I'd been testing - incorrectly - with a continuity meter, and couldn't find any connection between A1 and any of the other terminals, whatever the switch setting.

Yes - nothing with either continuity or resistance.

Yes - - no resistance.

Yes - 3.6k ohms, on both 1 and 2 (in/out). How OOI did you know that's the neutral?

Question for me now is how to make a decent connection between A1 and the live out. A Wago is my first port of call nowadays . . .

Thanks - do you have a link to that video? John Rumm I think was saying A1 should link to the live out (pin 4) - so that's good. But I think pin 3 is the live input, and pin 1 is the neutral input?

Life's never easy!

Can't find that one now. Here's another that covers two versions, neither has the same pin numbering as yours, and this one loops to live:

Yup, the coil resistance is probably too high to allow the meter to register "continuity" as such.

To an extent the neutral is the one you choose to be the neutral. On the

With the 5 terminal one, if you *don't* have any external emergency stop switches, then again it does not matter.

If you do have external switches than you will be looping one pole through the emergency switch loop of wire. So depending on which way round you connect L & N to the IN pins will dictate whether that loop is a live wire or a neutral. (the emergency switch will not care - it is just breaking the loop if required).

(In a static machine / workshop environment there is an argument for running a the neutral line through the emergency switches since that wire will be "unbalanced" (i.e. not a L & N pair in close proximity) that will carry a small amount of current (~60mA[1]), and there is less chance of interference with hearing aid loops if it at neutral potential rather than 230V)

A wago would be fine, however if you are crimping on spade terminals, then just crimp and extra short flylead wire onto the one going to the appropriate OUT terminal. You can then loop that back to A1.

Note that the A1 terminal is quite a bit smaller than the main ones. So it is not intended to be used as part of the main current carrying path through the switch.

Well on the bright side, if you get it wrong, all that will happen is that you end up making both ends of the solenoid neutral or both ends live. Nothing bad will happen other than the fact that it won't actually latch on as it should.

Understood - many thanks

Many thanks (and nib).

Oh yes it would. How many brakes have no actuator?

OP, this is one reason why the 5th terminal is smaller. It is only required to carry the operating current of a solenoid's coil.