Dear All,
I have come across a phenomenon that hope someone can explain – it’s stopping my relay (I think ) from de-energising.
I have 2 loads:
Load 1 and load 2.
Sometimes load 1 needs to be on. Sometimes loads 1 AND 2 need to be on. (Load 2 should never be on without load 1).
Control unit ‘A’ signals when load 1 should be on. Control unit B signals when loads 1 AND 2 should be on. These 2 control units can only give out a LIVE (or if modified will give out neutral).
Everything is ac - The loads use ac. The relay coil is ac.
So I went out and bought a double pole double throw relay with ac coil.
1. I wired a neutral to one side of the coil and control unit B (which gives out a live) to the other side of the coil.
2. To the common side of both contacts I wired live.
3. To the other of the normally open contacts one was wired to load1 and the other load2. The other sides of the load had neutral wired.
When control unit B came on so did loads 1 and 2. When unit B went off so did Loads 1 and 2. As expected.
To get Load 1 to come on by itself I wired control unit A direct to Load 1. – when control unit A was on so was load 1, when it was off so was Load 1 off as expected.
The problem arose when control unit A was on (and so load1) and remained on. Then control unit B was turned on, this would then bring load 2 on as well, as expected – but when control unit B was turned off Load 2 would remain on despite no live current being supple to the relay coil.
Control unit A was stopping the relay from releasing I think.
FIX1:
I thought maybe if I use 2 separate relays this would help. It did not.
FIX2:
This fix did work.
I modified control unit 2 to give out neutral and made the relay coil switch with neutral. Also I made Load 2 neutral switching, Load 1 remained live switching.
This time load 2 did not stick on when load 1 was already on.
What is going on here? And are there other modifications to overcome this problem?
Thanks
I have come across a phenomenon that hope someone can explain – it’s stopping my relay (I think ) from de-energising.
I have 2 loads:
Load 1 and load 2.
Sometimes load 1 needs to be on. Sometimes loads 1 AND 2 need to be on. (Load 2 should never be on without load 1).
Control unit ‘A’ signals when load 1 should be on. Control unit B signals when loads 1 AND 2 should be on. These 2 control units can only give out a LIVE (or if modified will give out neutral).
Everything is ac - The loads use ac. The relay coil is ac.
So I went out and bought a double pole double throw relay with ac coil.
1. I wired a neutral to one side of the coil and control unit B (which gives out a live) to the other side of the coil.
2. To the common side of both contacts I wired live.
3. To the other of the normally open contacts one was wired to load1 and the other load2. The other sides of the load had neutral wired.
When control unit B came on so did loads 1 and 2. When unit B went off so did Loads 1 and 2. As expected.
To get Load 1 to come on by itself I wired control unit A direct to Load 1. – when control unit A was on so was load 1, when it was off so was Load 1 off as expected.
The problem arose when control unit A was on (and so load1) and remained on. Then control unit B was turned on, this would then bring load 2 on as well, as expected – but when control unit B was turned off Load 2 would remain on despite no live current being supple to the relay coil.
Control unit A was stopping the relay from releasing I think.
FIX1:
I thought maybe if I use 2 separate relays this would help. It did not.
FIX2:
This fix did work.
I modified control unit 2 to give out neutral and made the relay coil switch with neutral. Also I made Load 2 neutral switching, Load 1 remained live switching.
This time load 2 did not stick on when load 1 was already on.
What is going on here? And are there other modifications to overcome this problem?
Thanks
Last edited: