complaints when using a hughes autoformer
I am looking at a used hughes autoformer. I know some parks rules say they are not allowed. Some parks we have been in, I have seen voltage at @ 102 to 104 with my a/c on. I would be using a PI 3o...
Forum Discussion
valhalla360 wrote:
Kind of scary as the standard design voltage is typically 120v +-10%, so below 108v starts getting sketchy.
SoundGuy wrote:ANSI C84.1 is the standard in N. America that applies to power companies. 120 volts is the standard "nominal" voltage. There are two ranges, one is Range "A" of +/- 5% of nominal and range "B" which is +6% & -13%. A poco can supply 104.4 - 127.2 volts and still meet voltage delivery requirements. Range B is only to occur on an infrequent basis. PG&E has a good explanation here.
Normal supply voltage in N America is sped'c to be 120 vac +/- 5%, meaning one should find unloaded source voltage no lower than 114 vac, no higher than 126 vac.
On top of that, there is voltage drop in feeders and branch circuits on private property. The NEC does not have a max. allowable voltage drop but has instead 6 recommendations which includes 5% total for a combined feeder and branch circuit.
Voltage can be as low as 99.2 (at the point of utilization) and still meet the ANSI standard and the NEC recommendations. Voltage drop can easily exceed 5% in older CGs/RV parks due to long runs of smaller gauge wire along with the higher demand of today's RVs.
Most electrical devices, equipment and appliances are designed and rated for 120 volt but some can be less like 110 or 115 volts (esp. motors) to account for presumed lower voltage at their terminals. AirXcel says "These air conditioners were designed to operate from a 115 VAC, 60 HZ, 1 Phase power supply" and couldn't find a min. voltage. Dometic states "The unit is a 115VAC, 60Hz appliance. The proper operating range is between 103 and 126.5 volts AC. " Just because they say the min. is 103 volts it doesn't mean that prolonged use at this voltage is perfectly okay. This is running voltage and during the momentary startup, the voltage can be waaay below what is good for the compressor & fan motors. Low voltage causes the motor windings to overheat and the damage is cumulative over time.
IMO, the SurgeGuard cutoff voltage of 102 is too low. I think even the PI 104 volts is too low and would prefer 105 or maybe a bit higher. Besides an EMS unit being highly recommended (as in almost mandatory), an digital/LED voltmeter permanently mounted inside is also highly recommended. Voltage can be rock solid at/near 120 or can go up & down like a yo-yo sometimes and down to near 104 where our EMS will cut out.
