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AC power regulator ideas

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TimK

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I need a simple way of regulating 110V AC power. I am working with a lot of industrial machines that use 110V AC hour meters. The min voltage is 110V and the max is 120V. The problem is that the transformers on these machines produce between 110V and 135V AC.

Any help would be great

Thanks
 
Does that cause a problem?, or are you just anticipating it 'might' cause a problem?.

You don't mention what power these machines are, but you can buy voltage stabilising transformers, which regulate the mains voltage.
 
Have you checked with the manufacturers' of the hour-meters? I doubt that that AC voltage range would be a problem.

Ken
 
The machines operate off of 480 3 phase but have transformers that provide 110V AC for control voltage. I am not 100% sure that the voltage is the problem but on some of the machines hour meters seem to fail allot more often usually within 300 - 400 hours. The voltage on these machines is 128-135V AC. And the hour meters seem to run hot. On machines with a more constant 110V the meters work fine.
These are a CRAMER 635G Meter - AC Voltage Hour and Minute Meters
Permanent magnet motor provides accuracy: ±50msec. per Start/Stop; 100% when running at nominal frequency. Input voltage: min. 110V, max. 120V; 60 Hz, 3 watts. Flange mounts in 2-1/4" dia. hole; mounting hardware included. Also includes 6" wire leads. Indoor use only. UL Recognized and CSA Certified. high-impact black styrene housing ,Whole numbers are white on black; decimal numbers are black on white Continuous-duty cycle.
 
You might try something as simple as a resistor in series with the meter? (I'm assuming it's just a crude motor device?), try something like 680 ohms 4W wirewound.
 
Another easy way to adjust the line voltage is the connect a small transformer in a buck or boost configuration. (attached). It does not "regulate", only changes. The relatively phasing connections determines whether you are adding or subtracting. The secondary's current rating must be equal to or greater than the load current. For an AC hour-meter you would only need a few tens of milliamps. And, little or no heat dissipation.

Ken
 

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You could just buy better meters too.

The self powered digital ones only need a contact that closes to activate them.
 
I use those same meters coming off 480 volt delta through control transformers in applications and have many that are a decade old. I use them for run time on pumps. They are supposed to be 110 to 120 VAC 60 Hz but most of mine are running around 127 to 130 volts. They use a small synchronous motor. Measure the current on one, I have no clue what they draw ansd as was suggested shove a resistor in series with it. Only recently have I started going to DC units for some applications but Cramer Hour Meters have been around for decades. Weird you are having problems.

Ron
 
Any commonalities with the enviroments the ones that fail?...temperature?...humidity?...vibration?

Ken
 
A resistor in series would be the easiest option and reliable.

I have inserted 1 k.ohm 2 Watt resistors in series with clock synchronous motors which were rated for 220 Volts and now running on 240 Volts form many years with no problems.

Try Nigel's solution in post 5.
 
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