Biodisc tripping motor

[Mark Reynolds]

Morning folks, I have a Kingspan Biodisc BA unit inherited when I bought the house 3 months ago.

it wasn’t maintained and as a result sludge built up and cause the unit to fail resulting in a new motor which we had fitted.

The company that came out initially wired it wrong resulting in the motor going backwards so I’m assuming it’s 3 phase?

I now have a problem where the power is tripped to the motor and the discs don’t move. I think I’ve narrowed it down to the pump in the pump chamber. If I turn it off the motor stays on but when the pump is turned on again it trips a while later, no pattern but I think it’s when the pump kicks in two or three times later?

Can anyone help with possible causes? I’ve dried out the electrical connections.

Thanks

Mark

 

[Gasguru]

Tripping what...an MCB, RCD, RCBO etc?

 

[Hugh Jaleak]

The BA is the small domestic unit, so I'd be very surprised if it had a 3 phase motor, but without looking cannot say for definite. (Impossible to wire a Single Phase so it runs backwards!) If you look in the wiring centre, single phase electrics will be 3 wires, Live Neutral and Earth, 3 phase will have 5 wires, the 3 phases, neutral and earth.

If the issue is with the pump, then it will need replacing, there are unlikely to be any user serviceable parts inside. I'd imagine the pump operates on a float switch so will only kick in when the level rises sufficiently for it to be required, (the discs need to rotating constantly.) Possible moisture has got inside the casing, unfortunately any submersible pump in this type of application will not last forever.

If you haven't had the unit desludged, then I'd also recommend you do so. If you're not used to a septic tank, then nothing to go down the WC that hasn't been though you first, (apart from Toilet Tissue of course!), keep use of bleach, cleaning chemicals, detergents, etc down to a minimum.

 

[Mark Reynolds]

The BA is the small domestic unit, so I'd be very surprised if it had a 3 phase motor, but without looking cannot say for definite. (Impossible to wire a Single Phase so it runs backwards!) If you look in the wiring centre, single phase electrics will be 3 wires, Live Neutral and Earth, 3 phase will have 5 wires, the 3 phases, neutral and earth.

If the issue is with the pump, then it will need replacing, there are unlikely to be any user serviceable parts inside. I'd imagine the pump operates on a float switch so will only kick in when the level rises sufficiently for it to be required, (the discs need to rotating constantly.) Possible moisture has got inside the casing, unfortunately any submersible pump in this type of application will not last forever.

If you haven't had the unit desludged, then I'd also recommend you do so. If you're not used to a septic tank, then nothing to go down the WC that hasn't been though you first, (apart from Toilet Tissue of course!), keep use of bleach, cleaning chemicals, detergents, etc down to a minimum.

Thanks Hugh

it’s 3 phase based on what you say, it has 5 wires going into it.

I’ve disconnected the pump and de sludge pump and still it trips, so I suspect it’s not the right motor

regards

Mark

 

[Mark Reynolds]

If you haven't had the unit desludged, then I'd also recommend you do so. If you're not used to a septic tank, then nothing to go down the WC that hasn't been though you first, (apart from Toilet Tissue of course!), keep use of bleach, cleaning chemicals, detergents, etc down to a minimum.

it was cleaned and desludged the day after the new motor was fitted

 

[Mark Reynolds]

The BA is the small domestic unit, so I'd be very surprised if it had a 3 phase motor, but without looking cannot say for definite. (Impossible to wire a Single Phase so it runs backwards!) If you look in the wiring centre, single phase electrics will be 3 wires, Live Neutral and Earth, 3 phase will have 5 wires, the 3 phases, neutral and earth.

If the issue is with the pump, then it will need replacing, there are unlikely to be any user serviceable parts inside. I'd imagine the pump operates on a float switch so will only kick in when the level rises sufficiently for it to be required, (the discs need to rotating constantly.) Possible moisture has got inside the casing, unfortunately any submersible pump in this type of application will not last forever.

If you haven't had the unit desludged, then I'd also recommend you do so. If you're not used to a septic tank, then nothing to go down the WC that hasn't been though you first, (apart from Toilet Tissue of course!), keep use of bleach, cleaning chemicals, detergents, etc down to a minimum.

My mistake, it has 4 cables, L N E and a black cable

 

[bernardgreen]

(Impossible to wire a Single Phase so it runs backwards!)

Not true. Most AC induction motors have two field windings in the stator. Magnetically they are about about 45° out of phase.

One coil is fed direct from the AC supply and the second one is fed via a RUN capacitor as apposed to a START capacitor

Reversing the connections to one of the coils will result in the motor rotating in the opposite direction.