Hi all,
I had a 10A 12V power supply today of which is switching 2 x 2A 12V pumps wired in paralel. I had a relay switching the primary side of the transformer...This was working fine until yesterday when I put my hand in the tank and got an electric shock!
I was then measuring 30 - 100V between + or - of the 12V secondary side (+ and - was giving 12.7V) to the concrete floor of the garage I had the pump running in. When I measured to earth on the back of a socket between the + or - I was getting 88 volts.
The meter was saying the polarity was correct if I connected the black lead to + or - of the secondary 12V side and the red leas to earth..if I connected it the other way round it was saying reverse polarity.
I then went off and bought another 12V 10A power supply and connected it as before then after a while the 8A relay switching the primary side stuck on (burnt out)
Should I be switching the primary or the secondary of the transformer? I think switching the primary caused the transfomer to burn out but I have no idea why it would give 88V to earth from the secondary of a 12V transformer of which was giving a steady 12.7V between + and -
Anyone any ideas please?
Thanks
I had a 10A 12V power supply today of which is switching 2 x 2A 12V pumps wired in paralel. I had a relay switching the primary side of the transformer...This was working fine until yesterday when I put my hand in the tank and got an electric shock!
I was then measuring 30 - 100V between + or - of the 12V secondary side (+ and - was giving 12.7V) to the concrete floor of the garage I had the pump running in. When I measured to earth on the back of a socket between the + or - I was getting 88 volts.
The meter was saying the polarity was correct if I connected the black lead to + or - of the secondary 12V side and the red leas to earth..if I connected it the other way round it was saying reverse polarity.
I then went off and bought another 12V 10A power supply and connected it as before then after a while the 8A relay switching the primary side stuck on (burnt out)
Should I be switching the primary or the secondary of the transformer? I think switching the primary caused the transfomer to burn out but I have no idea why it would give 88V to earth from the secondary of a 12V transformer of which was giving a steady 12.7V between + and -
Anyone any ideas please?
Thanks