Blinking Lights

[markstg]

At my house I have a 5 ton, 2 stage scroll compressor condensing unit, and my house lights blink on the unit starting.
Specs are 118 LRA, 230V, 23 FLA.

Lamps are incandescent 130 V.

Measurements at the unit disconnect switch are:
Normal Voltage 246 V

Starting Voltage: 231 V
Starting Amps: 121 A

Running Amps: 10 A (Low Stage)

Starting time: 1 second.
Start is on Low stage.

This is on a 1 year old house and has done this since installed.
There is no issue when the compressor goes from low stage to high stage.

Neutrals have all been checked, Meter, Panelboard, AC unit/disconnect, and are all tight.

If I place a hard start (start assist) kit (Capacitor and Start Relay) on the compressor, will it reduce the line current to the unit, so that my service doesn't see the full compressor start current? If so, any guess at how much less.

 

[don_resqcapt19]

Without a transformer way bigger than what the utility will provide without a hefty monthly extra charge there is likely no way to get rid of the voltage dip that is caused by the compressor starting.
A hard start kit will reduce the current and also the voltage dip, but I expect it will still be noticeable, especially with 130 volt lamps on a 120 volt system.

 

[markstg]

I thought the 130V lamps would be making the problem worse. Geeez just want longer life lamps.

I have a voltage recorder on my meter from the power co. Will hear next week what they say about the voltage dips.

 

[broadgage]

I would replace the lamps with LED lamps, be certain to get lamps that are warranted for operation down to 85 or 90 volts.
This wont of course actually reduce the voltage drop, but will substantialy reduce and probably eliminate the displeasing lamp flicker on AC starting.

The LED lamps will use a lot less energy and if of reputable make will also outlast numerous filament lamps.
Presuming that the lamps are in the conditioned space, then the reduced heat from the lamps will also slightly reduce the energy used for cooling.

 

[markstg]

I would replace the lamps with LED lamps, be certain to get lamps that are warranted for operation down to 85 or 90 volts.
This wont of course actually reduce the voltage drop, but will substantialy reduce and probably eliminate the displeasing lamp flicker on AC starting.

The LED lamps will use a lot less energy and if of reputable make will also outlast numerous filament lamps.
Presuming that the lamps are in the conditioned space, then the reduced heat from the lamps will also slightly reduce the energy used for cooling.

LED lights are not an option, as all my dimming switches which are controlled by my automation system won't work with LED's.

thanks for the input.

 

[kwired]

Without a transformer way bigger than what the utility will provide without a hefty monthly extra charge there is likely no way to get rid of the voltage dip that is caused by the compressor starting.
A hard start kit will reduce the current and also the voltage dip, but I expect it will still be noticeable, especially with 130 volt lamps on a 120 volt system.

This is typically the problem, sometimes coupled with long service conductors and associated voltage drop.

Assume that many times in residential areas a 25 kVA transformer is standard and supplies multiple services. Your instantaneous locked rotor current is at least 118 amps, (on a tranformer with a full load rating of 104 amps) but probably higher then that for a few microseconds, this is what is drawing voltage down. Then consider that you as well as other customers are already running loads from that transformer lessening the capacity to deliver to starting this compressor.

A hard start kit is nothing more then a higher value capacitor to give more phase shift to get the compressor started. If anything it will cause even more current to be drawn, but for shorter duration, gets a little complicated when the supply can't necessarily deliver what the unit would otherwise want. Other then to have the ideal situation of larger supply transformer and/or larger supply conductors you probably really want to see some sort of reduced voltage starting method employed here, to lessen the starting current. Something that is not as common on single phase motors, but could be done.

Low or high stage doesn't matter. You are still starting the same motor from a stopped position with a full voltage starting method. Most two stage compressors are a single speed driven motor and the high/low stages is achieved by solenoid valves in the refrigerant line to control flow of refrigerant, compressor just draws less when less load is applied to it, is running at full voltage and speed otherwise.

 

[mgookin]

Do your neighbor's lights go down as well?

 

[Little Bill]

Without a transformer way bigger than what the utility will provide without a hefty monthly extra charge there is likely no way to get rid of the voltage dip that is caused by the compressor starting.
A hard start kit will reduce the current and also the voltage dip, but I expect it will still be noticeable, especially with 130 volt lamps on a 120 volt system.

I'm not seeing how 130V lamps would make any difference in the dimming. As far as I know, the only difference in a 130V lamp/bulb and a 120V one is the 130V has larger filaments. The larger filaments are to handle the higher than 120V that many services experience.

I'm not necessarily disagreeing but not understanding how the 130V lamps would make any difference.
Are you saying, for instance, if you had exactly 120V incoming to a fixture that a 130V lamp it would not be as bright as a 120V lamp? And if you had a voltage dip it would be even more noticeable?

 

[GoldDigger]

The 130V lamp will have its filament at the optimum temperature to balance light output against bulb life when connected to 130V.
At 120V it temperature (and hence color temperature) will be lower. The light output will be lower and yellower than at 130V.
If you pay for your electricity, you will spend more for extra power than you save in cost of light bulbs.
The exception is when it is very difficult (hence expensive) to replace the bulb.

Tapatalk!

 

[Little Bill]

The 130V lamp will have its filament at the optimum temperature to balance light output against bulb life when connected to 130V.
At 120V it temperature (and hence color temperature) will be lower. The light output will be lower and yellower than at 130V.
If you pay for your electricity, you will spend more for extra power than you save in cost of light bulbs.
The exception is when it is very difficult (hence expensive) to replace the bulb.

Tapatalk!

I should have mentioned that from "ohms law" perspective I understand the difference. But didn't consider that at only a 10V difference the light would be noticeably different.
Didn't consider color temperature.

 

[ActionDave]

How many 120V bulbs do I need to stock up on to make sure I don't outspend my 401K?

 

[Little Bill]

How many 120V bulbs do I need to stock up on to make sure I don't outspend my 401K?

Lets see:
401k=41000
41000-120=40880
so I would say not more than 40879 to stay under the 40880.

 

[LEO2854]

Do your neighbor's lights go down as well?

Yes they do....

 

[mgookin]

Sounds like poco already is on it. Let's see what they say.

 

[StarCat]

Start Gear

Start Gear

I have dealt with this effect extensively as an HVACR Tech back in the 90s when Copeland and Carlyle were getting the kinks out of the then new scroll design.
Hard Start components will improve the starting characteristics to a degree.
The main thing I noted and it always did help was, start componentst will trim down the peak inrush current on start.
In essence its a quicker start.
This is easily seen on a recording type ammeter such as the Fluke 87.
The start gear must be the exact set specified by the MFG for the compressor in question.
PTC start gear can also work well but it must be carefully applied with respect to the original OEM wiring of the condenser. It cannot be used with single pole shunt type contactors.

 

[markstg]

The 130V lamp will have its filament at the optimum temperature to balance light output against bulb life when connected to 130V.
At 120V it temperature (and hence color temperature) will be lower. The light output will be lower and yellower than at 130V.
If you pay for your electricity, you will spend more for extra power than you save in cost of light bulbs.
The exception is when it is very difficult (hence expensive) to replace the bulb.

Tapatalk!

From the Specs on the BR40, 130V, 65 W lamp:
when operated at 120V watts used 59W, lumens 383
when operated at 130V watts used 65W, lumens 510
Life is increased, watts are reduced, lumens (brightness) are reduced on 130V incandescent lamps operated at 120V.

 

[kwired]

I used to prefer 130 volt lamps myself, now even though the incandescent lamps are supposed to be "retired" you still can find them, but you don't get as much selection anymore. Nominal voltage is 120 volts, but actual operating voltage many times around these parts is closer to 125, meaning the 120 volt lamps will not last as long as they were supposed to, and they are somewhat short life to begin with. Going with 130 watt lamps meant a little less light but long enough life to be worth what you give up.

 

[markstg]

Well seems the jury is still out on whether the line current will increase, decrease, stay the same when a hard start kit is added to a scroll compressor. I just don't want to spend $200 to find out, ( Carrier start assist kit, they are proud of their equipment, plus service charge).

Will post on any updates.

thanks

 

[don_resqcapt19]

..
Are you saying, for instance, if you had exactly 120V incoming to a fixture that a 130V lamp it would not be as bright as a 120V lamp? And if you had a voltage dip it would be even more noticeable?

That is exactly what I think happens.

 

[markstg]

From the Specs on the BR40, 130V, 65 W lamp:
when operated at 120V watts used 59W, lumens 383
when operated at 130V watts used 65W, lumens 510
Life is increased, watts are reduced, lumens (brightness) are reduced on 130V incandescent lamps operated at 120V.

The 120V, 65W rated lamp has a lumens of 630

I'm going to get a few 120V lamps and check out if the dimmimg is less perceptable.