Wiper inefficiencies - intermittent or low speed better

[scottf200]

So in my laymen terms: Because of start up load of a motor is, it more efficient to run the wipers at low speed instead of intermittent as the motor (I presume) is starting and stopping every X seconds?

Video showing continuous motor running when wipers are on: http://www.youtube.com/watch?v=PMxBKlfQ1IY

Background:
http://hvac-talk.com/vbb/showthread.php?1125761-AMPS-R-L-A-F-L-A-L-R-A&p=13654251#post13654251

LRA - Locked Rotor Amps: The current you can expect under starting conditions when you apply full voltage. It occurs instantly during start up.
RLA - Rated Load Amps: The maximum current a compressor should draw under any operating conditions. Often mistakenly called running load amps which leads people to believe, incorrectly, that the compressor should always pull these amps.
FLA - Full Load Amps: Changed in 1976 to "RLA - Rated Load Amps".

How many watts will a 2.2kw motor draw on starting?
http://answers.yahoo.com/question/index?qid=20130830102851AAjid2j

Your compressor will draw about six times there normal running current when it starts. So lets get that first.

Assumptions I have to make since you did not provide adequate information are these:
1)Starting current is 6 times running current
2)Operating power factor for this motor under normal load is 0.80
3) The single phase rate voltage to operate this motor is 240 volts

You will have to adjust your numbers based on what the actual figures are.

- Running kVA = kw/power factor = 2200 / 0.8 = 2,750 VA
- Current = 2750vA / 240 volts = 11.46 amps.
- Starting current = 6 * 11.46 amps = 68.8 amps.
- Your inverter must supply this staring current and not drop the supplied voltage any more than 10% or go no lower than 216 volts during start up..
- The inverter rating will have to be about 16.5 kVA for starting this motor load. Especially is the compressor does not have an unload-er valve for the compression pistons.

 

[jerry33]

1. The wiper uses so much less energy than powering the car, it's hardly worth worrying about.

2. If you clean your windows with Chemical Guys cleaner or some similar product, you'll seldom need to use the wipers.

3. As far as the compressor goes, it's variable speed so how much energy it uses is highly dependent upon how you set it. I've found that it doesn't use very much here in Texas.

 

[scottf200]

1. The wiper uses so much less energy than powering the car, it's hardly worth worrying about.
2. If you clean your windows with Chemical Guys cleaner or some similar product, you'll seldom need to use the wipers.
3. As far as the compressor goes, it's variable speed so how much energy it uses is highly dependent upon how you set it. I've found that it doesn't use very much here in Texas.

I wasn't really worried about the impact to our EV driving range. It has been a curiosity question on and off for quite a while and I've just forgot to do any research and post the question.

Thanks for the link. I'm guessing it is similar to Rain-X but I'll check it out.