Quote:
Originally Posted by CountryB
How does the Voltage Regulator work?
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It's a step-up transformer. When supply voltage drops below a predetermined value a relay closes and changes the effective winding turns ratio to step the output voltage up by about 10%. When input voltage rises above some threshold, it goes back to bypass, or small step-up in output voltage.
Quote:
Originally Posted by CountryB
If the campground is supplying low voltage (say 100 VAC) at the pedestal, does the voltage regulator bump it up to 110V or 120V, and how long will it continue to do that (is it intended for short term use or will it bump up voltage for a couple of days continuously)? Does it get hot?
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AFAIK, they're continuous-duty rated. There will be some small energy loss, as in every transformer, but it's small. Losses manifest themselves as heat.
Quote:
Originally Posted by CountryB
I assume if the VR is increasing voltage it must be pulling more amperage from the pedestal.
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Not necessarily. For a purely resistive load, like an electric resistance heating element (electric oven, toaster, heat strip, space heater), increasing the output voltage will increase the current through the load and therefore increase the current from the pedestal. For reactive loads, like motors and chargers/converters, see below.
Quote:
Originally Posted by CountryB
So if I have 3 roof AC units on and the TV and I'm pulling 45A (I'm making that number up) and the voltage from the pedestal is only 100 VAC could the Voltage Regulator cause the amperage at the pedestal to exceed 50A and trip the breaker?
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A/C units have induction motors which operate under fixed load conditions since a compressor at speed has an essentially constant load. Same with a fan. A 1 hp shaft load on the motor that's driving the compressor will not change with voltage changes at the motor leads. BUT, as will all induction motors, dropping the voltage will result in an increase in current drawn (P=V x A, ignoring efficiency and power factor). Using a boost transformer will increase the voltage at the motor leads, resulting in a decrease in current through those leads. But back at the pedestal, the current drawn will increase as the voltage droops regardless of the presence or absence of a boost transformer. You'd be drawing more current even without a boost transformer.
All the boost transformer does is increase to the voltage to the motors, which allows them to draw less current and therefore run cooler and at a higher efficiency. The hotter the windings, the shorter their anticipated life (rule of thumb is, every 10 deg. C/18F increase in temperature halves the statistical life of motor/transformer winding insulation).
But without boosting the voltage, A/C units will draw more current from the pedestal as the pedestal voltage sags. With the boost transformer, the A/C units will still draw more current from the pedestal as the pedestal voltage sags, but the motors won't feel it due to the transformer doing its thing.
So in summary:
-Resistive load with sagging voltage, no boost transformer = reduced current draw from pedestal and reduced output from heating element.
-Resistive load with sagging voltage, with boost transformer = increased current draw from pedestal and increased output from heating element.
-Inductive load with sagging voltage, no boost transformer = increased current draw from pedestal, increased current through load, same output from load.
-Inductive load with sagging voltage, with boost transformer = increased current draw from pedestal, decreased current through load, same output from load.
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