Polarity light on my PMS 4

[Anthony_374304842]

Hi

I am new to caravanning i am a bit worried every time i connect my generator up to my caravan a polarity light comes on my PMS 4 unit. The book says you need to reverse the polarity but i'm not sure how. When i couple up to the mains hookup the polarity light does not come on. Now i think i have damaged the transformer / charger unit built into th PMS 4 as it not longer seems to charge.

Any advice would be very welcome

Thank

Tony

 

[ProfJohnL]

Hello Anthony,

For you and your family's safety, have the system checked out by a competent electrician.

 

[Damian]

I agree with John on this one.

Having had the problem the first time you connected the genny, why did you do it again? before getting adice.

You have , at best, blown a fuse, or at worst completely destroyed the charger unit, which are not cheap to replace.

You need the genny oulets checked with a polarity tester, as it seems that maybe the person wiring them up has reversed the pos and neg.

 

[Rod_5041370]

If I recall correctly, even if you swap the live & neutral in your caravan hook-up lead your polarity light will still be on.

Portable generators do not normally follow the"live/neutral" concept and do not provide a proper earth unless you drive an earth rod into the ground.

I must confess that I ignore polarity when I run on my generator but I do have a continental caravan which has breakers on both live & neutral.

 

[Rod_5041370]

If I recall correctly, even if you swap the live & neutral in your caravan hook-up lead your polarity light will still be on.

Portable generators do not normally follow the"live/neutral" concept and do not provide a proper earth unless you drive an earth rod into the ground.

I must confess that I ignore polarity when I run on my generator but I do have a continental caravan which has breakers on both live & neutral.

Re. your non charging.

You don't say which generator you are using but the incorrect polarity will not destroy the charger, however, the output waveform and spikes from a cheap, non-inverter generator has been known to.

 

[rob_jax]

Hi Tony,

Correct operation of AC appliances is not dependent on polarity, but safe operation of appliances in UK is dependent on polarity - because the UK only switches the wire designated as "live".

As Rod pointed out, European made caravans, like our Eriba (Hymer), switch both live and neutral and the polarity of the mains input doesn't matter.

So, polarity shouldn't have damaged the PMS unit, but your generator might have. Why? Because unless you have a quality generator (Honda about

 

[Anthony_374304842]

Hi Robert and to all that have replied.

I fear what you have suggested maybe the case. My friend had said to me in the past he thought he heard my Genny surge ( if thats the right word) and yes it was a cheap generator.

I guess i will have to invest in a new PMS unit and a new generator and hope that cure the problem.

However my friend has a Kippor and it too lights up the polarity light. I am right in saying that this shouldn't be a Problem?

Sorry about this but i am very new to caravanning

Thank

Tony

 

[rob_jax]

Hi Tony,

Surge describes the generator over-speeding (and producing more volts than needed) quite nicely.

Surge happens because the electrical load changes - turn an appliance on or off, this changes the load on the generator, and the engine speeds down (appliance on) or up (switch something off).

The worst case is when you switch off - the engine instantly speeds up for a few seconds - and 350 volts has headed down the wire to your caravan. You can sort of handle this by never switching any appliance off - only the generator - but a bit risky (if you are prone to forget)

Or the carburettor is "cr@p" and won't hold a steady throttle position - so that it surges under constant load - in which case it's really unsuitable

Don't throw away the PMS charger - it's probably only a simple component that has died - and it's worth seeing if it can be economically repaired - speak with the makers.

Polarity light - could be that they are wired up incorrectly - or that it's a false triggering of the polarity light because the generator isn't earthed.

Robert

 

[JeremyClarksson]

Where do you get these PMS polarity lights?

It would be very useful knowing what mood she is in!

 

[gary]

I can clear up the problem with the polarity light, my van has a PMS-5 and I was look this evening through my van manual, it says;

While using some generators the polarity light may show, this is normal and can be ignored.

To all intents and purposes it matters not which number comes after 'PMS' they all work the same so equally applies to the 4.