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Old 12-07-2012, 07:01   #1
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cruisair compressor power

It is a dual split system 16k type f.
on our poor shore power, I measured voltage at the compressor and it is 107 and 57 cycles when running.

Running on gen it is 121 and 60 cycles.

It refuses to do a cold start on shore power, but if your run on gen for a few minutes and switch to shore it will run. Would that poorer power hurt the compressor at all?

I think I figured out the noise is slightly louder when running on the poor shore power we have cause which is free.

I used a stick to listen to compressor running and it is quieter on the gen than on shore power, if that makes any sense. Have to do that since gen noise overwhelms the cruisair noise.

On shore power it sounds about like my inlaw's heat pump compressor or mine at the house.

With a stick or metal rod channeling the noise you get to hear a lot more various noises. It sounds very smooth running.
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Old 12-07-2012, 08:32   #2
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Re: cruisair compressor power

Low voltage can lead to overheating, shortened life, reduced starting ability, and reduced pull-up and pullout torque. The starting torque, pull-up torque, and pullout torque of induction motors all change, based on the applied voltage squared. Thus, a 10% reduction from nameplate voltage (100% to 90%, 230V to 207V) would reduce the starting torque, pull-up torque, and pullout torque by a factor of .92.9. The resulting values would be 81% of the full voltage values.

In this case, it is easy to see why it would be difficult to start “hard-to-start” loads, like you’re a/C compressor, when the voltage happens to be low.

When you subject a motor to voltages below the nameplate rating, some of the motor's characteristics will change slightly and others will change dramatically. To drive a fixed mechanical load connected to the shaft, a motor must draw a fixed amount of power from the line. The amount of power the motor draws has a rough correlation to the voltage 2current (amps). Thus, when voltage gets low, the current must increase (proportional with the decrease in voltage) to provide the same amount of power. An increase in current is a danger to the motor only if that current exceeds the motor's nameplate current rating. When amps go above the nameplate rating, heat begins to build up in the motor. Without a timely correction, this heat will damage the motor. The more heat and the longer the exposure to it, the more damage to the motor.
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"

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Old 12-07-2012, 09:54   #3
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Re: cruisair compressor power

ok, still even though not ideal, does anyone know if running this AC at lower power would hurt anything. I had read somewhere that cruisair could run down at 100 volts. Who know if that is true for mine?

I found the trick to start when shore power was lower quality was to run on gen which sets up the pressure differential so then motor has easier time to start up. Which seems odd as at that time head pressure is high and suction low. Maybe the fluid flow of the refrigerant is helping here. I had read this on my trolling of the net for info on cruisair and it did work for mine.

I did find this here and is for the SMX controlled AC units

would this still apply to my rotary knob unit. the compressor was replaced in 1993 and the system original install was in 1971.

I would think this following comment was a normal start and then power starts dropping.
Low-Voltage Shutdown
The low-voltage protection feature is always active. If AC line
voltage drops and remains below the limit, 100 volts for a
115V system or 200 volts for a 230V system, for more than
three minutes, the SMX II shuts down the entire system. The
display will flash “LO/AC”. This is a sustained shutdown, and
the system will not resume operation even if the line voltage
rises to normal levels. To reset, press the Off key
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compressor, cruisair

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