pure curiosity. ..solanoid tripping electrics. .

[suavegit]

Hello fellas.

New to the forum and not overly technical from electrical point of view. Had two incidents of solanoids on oil pumps tripping out the electrics and would like to know technical reason. Similar I suppose to your system pumps doing the same thing?

Would appreciate anyones knowledge on said subject

Cheers in advance

 

[RF Lighting]

Were they new units, or something which had been working fine and just started to trip the power?

 

[suavegit]

Old boilers. Both were trianco boilers, danfoss solanoids. They couldnt give me a definate answer ' not come across that before'

 

[RF Lighting]

I presume the wndings must have failed causing a short circuit. Were the solonoids ceased or did they seem mechanically sound?

 

[suavegit]

Weird. Resistance ok and as should be but as soon as powered it tripped everything. Always thought windings but didnt know how if you know what I mean. How do the windings create a short? No moving parts as such?

 

[RF Lighting]

If the windings overheat, it melts the enammel coating off the copper wiring causing a short.

When you say resistance ok, did you measure end to end of the coil? Also did you carry out an insulation resistance test between each end of the coil and earth?

What was the device which tripped? Was it a fuse / circuit breaker or and RCD?

 

[suavegit]

Thanks. Tripped out consumer unit both times although really one was just an old fuse board from dark ages. Thinking back I only checked resistance on first one but not to earth.... Went from one terminal to other and sure resistance ok.....was a while ago! Never been shown but always keen to learn. So should do a resistance test from earth aswell then ?what should I be looking for?

 

[Agile]

Unfortunately you have not clarified if the problem is tripping an MCB on current overload or an RCD on earth leakage.

Since the coils are wound with very thin wire whioch woulkd probably fuse before they tripped an MCB its almost certainly and RCD.

So its the leakage to earth which you need to measure.

Unfortunately its not that easy. Often measuring at low voltage will not show any problem. But with 500v using a Megger style insulation measuring instrument will show up the problem.

Tony

 

[suavegit]

Thanks tony. All I can remember it was tripping the whole house both times. Megger is out of remi as more a gas/oil engineer.Appreciate the help.

 

[Mikefromlondon]

How is your earth wire laid? I recon your solenoid when energised causes the whole house to trip over the loose earth wire as the magnetic field collapses on the solinoid, this causes the back electromotive force to exceed 1000volts and this jumps over the loose and bare earth, so you need to make sure your earthings are OK. as this would otherwise cause your house to flip over!
































That was a joke OK.