ECN Forum Forums General Topics of the Trade General Discussion Area a/c load lights dimming

Resqcapt19... lights dim ?? That is the first thing that I would think is a loose neutral. Light's .. not a 240v line to line. Have not been on ENC for over a year ! This is fun checking back ! whyrag

Guys,
Do your A/C units use Soft-Start/Current Ramp up technology?.
This would seriously reduce the Start-Up in-rush current, which by experience is 5-7 times FLA.
Just wondering.

Would adding start capacitors help?

I ran into this same problem this summer,on a house I wired last year. Have 15 ton of A/C in it. FLA of each of the three compressors was 32 amps. Lights dimming bad and VD was10 to 13 volts. Customer was not happy when we told him he has to live with it, cause it would be costly to try to correct it. I was thinking about an Isolation transformer, Any thougths? We meaning myself and the hvac installer.

Pinemarten,
Air Con units already have starting Cap's, as a matter of course, for both the fan and the compressor.
Most compressors are split-phase anyway, as far as single phase ones go.
3 phase compressors are self-starting.
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ElectricmanScott:
You wouldn't by any chance have a loose Main Neutral by any chance?, I've seen this happen before!.
[Message edited to add further comment]

[This message has been edited by Trumpy (edited 10-04-2003).]

A hard start kit is the way to go. I put one on for a customer the other day and it worked perfectly. Very easy to install, it just clips onto the existing start capacitor. The part number was SPP6 (I think) and the cost was $13 at Johnstone Supply.

Others here have given good advice. Be cautious when 'finger pointing' that findings are based on a known-accurate {NIST-traceable} meter.

Regardless of the severity of perception of lamp flicker, the usual ANSI 'standard' acceptable range is typically 108/216-126/252 volts at the building service entrance. Utilities often use that value to determine whether it's a "your problem or ours" issue.

Some utilities are regulated by state PUCs to have somewhat tighter numbers. An example is §C of http://www.pge.com/customer_services/business/tariffs/doc/ER2.doc




[This message has been edited by Bjarney (edited 10-04-2003).]