RE: RV Park Low Voltage Remedies?

[RamblingWreck]

 
A co-worker was just relating an experience he had with his motor home.  Upon arrival at RV Park one summer evening he used a voltmeter to check voltage before hooking up and found it to be 115V.  Next day as the temperatures rose, campers turned on their A/C units.  After running for awhile his failed.  He checked incoming voltage and found that it had dropped to around 55V.  
 
 The low voltage caused his A/C compressor to fail and the repair bill was $400.  The RV park refused to pay for the repair.  He spent the rest of his vacation running his generator.
 
 My company sells computerized equipment worldwide.  In third world countries we generally recommend that customers purchase a voltage regulating transformer.  My experience is that these work well.
 
 My questions:
 
 1) Are there voltage regulating transformers designed for 30 Amp service like that used for a popup?
 2) If they exist, how large are they, where is a good place to install one and are they quiet?
 3) Are heat pumps less susceptible to damage from low voltage than an A/C unit?
 
 Rambling Wreck
 

[mike4947]

 RamblingWreck
Yes there are stepup or " guardian"  units. Now for the bad news the last time I looked on that would gaurantee voltage levels with park voltages at 55 volts would weight in excess of 200 pounds and cost several thousand dollars.
 Sounds like your friend fibbed a little on the voltage level. At 55 volts the amperage draw would have more than doubled (110 divided by 55 equals 2 plus heat related wire resistance losses) and every fuse and breaker in the park would have blow. Low voltage in parks usually run in the 95 to 100 volt range which will give what at home would be called a Brown out. Because all the lights dim down to the point of looking brown. This is plenty low enough to ruin electronics and motors
 Suggest to your friend the answer is to not only check the voltage once but several times a day in crowded parks. Up north I ve found the condition occurs more at evening when everyone fires up the electric heaters.
 
 PS: it wasn t really the compressor it was the electric motor driving it, so heat pumps will be similarly affected. As will 12 volt sytems. Your converter is also just a rectifier plus a transformer and can t compensate for the reduced voltage ie. 110AC in 12DC voltage out then 90 volt AC in you get apx 10 volts out. Not enough to run most 12 volt sources and the amperage draw also increases the 20% the voltage dropped.

[AustinBoston]

 mike4947

ORIGINAL:  mike4947
 PS: ...As will 12 volt sytems. Your converter is also just a rectifier plus a transformer and can t compensate for the reduced voltage ie. 110AC in 12DC voltage out then 90 volt AC in you get apx 10 volts out. Not enough to run most 12 volt sources and the amperage draw also increases the 20% the voltage dropped.

 This is seldom (if ever) true any more.  Many (probably most) modern switching power supplies can easily handle input voltages ranging from about 85 volts to 250 volts.  Switching power supplies do not require a power transformer, are more efficient, lighter, and usually less expensive than the older style transformer-recifier-linear regulator style.  For higher power units (more than 20 amps @ 12VDC), they often cost less than just the transformer!  The one drawback I have found is that they can produce EMI/RFI noise (radio/TV interference) if not properly shielded and/or filtered.  They will draw more current if the voltage drops because they can t change Ohm s law.
 
 BTW, if the output voltage did drop from 12 to 10 when the input voltage dropped from 110 to 90, there would NOT be a significant increase in input current.
 
 Austin