AC outlets 83V

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Dec 1, 2018 | 03:27 PM

adamsfbay

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Mountain Pass

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From: SF Bay Area

AC outlets 83V

I measured the in-cab outlets and found they were both 83V is this normal?

Dec 1, 2018 | 03:48 PM

skanj0

More Turbo

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Quote:

Originally Posted by adamsfbay

I measured the in-cab outlets and found they were both 83V is this normal?

83v with the motor running? That cant be right. Should be between 115v and 120v.

Dec 1, 2018 | 04:01 PM

Section179

Fleet Mechanic

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Are I you using a digital voltmeter set to AC?

Dec 1, 2018 | 04:10 PM

DSLTRK60

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From: Phelan CA

The inverter probably uses pwm or pulse width modulation to synthesize a sine wave. In other words it's not a pure wave inverter.

Common multimeters are designed to measure the rms voltage of a clean sine wave only, hence the low reading of 83 volts.

The only way to know is to look at the wave form with an occilloscope.

Dec 1, 2018 | 04:14 PM

DSLTRK60

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From: Phelan CA

Here is what pwm looks like. The main thing is the area under the waveform(power) is equivalent to the sine wave.

Dec 1, 2018 | 06:27 PM

BillyE

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Use a “true rms” meter and you should get 110-120. It sounds like you’re using an averaging meter.

Dec 1, 2018 | 06:51 PM

adamsfbay

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Mountain Pass

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From: SF Bay Area

Thanks, makes sense (re:averaging)

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Dec 2, 2018 | 06:55 AM

crewzer

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From: Mills River

The OEM inverter output is MSW (modified sine wave or modified square wave; take your pick). It's not a true sine wave (TSW), nor is it PWM.

Here are links to previously posted waveform pictures:

https://www.ford-trucks.com/forums/showpost.php?p=17276759&postcount=46
https://www.ford-trucks.com/forums/1...l#post17937128

Here are links to previous discussions about the inverter and associated operational problems:

https://www.ford-trucks.com/forums/1...l#post17270170
https://www.ford-trucks.com/forums/1...l#post17936436
https://www.ford-trucks.com/forums/1...l#post18298129

HTH,
Jim crewzer