Help with Motor

[florinm16]

I have receive a call to fix a tripping breaker for a/c compresor motor is one phase 120 v , 2.25kw so that's mean 3 hp . Breaker is 30A and is tripping after motor starts , any idea what size of breaker i have to use ? i was thinking to run new lines from panel but i don't have experience with motor . Thanks.

 

[jim dungar]

I have receive a call to fix a tripping breaker for a/c compresor motor is one phase 120 v , 2.25kw so that's mean 3 hp . Breaker is 30A and is tripping after motor starts , any idea what size of breaker i have to use ? i was thinking to run new lines from panel but i don't have experience with motor . Thanks.

Check your load requirements again.
For a 120V 3HP 34A motor I would have used a 70A breaker.
Be careful not to convert the KW input of a load to the HP output of a motor, by simply using the multiplier 746W/HP.

 

[growler]

I have receive a call to fix a tripping breaker for a/c compresor motor is one phase 120 v , 2.25kw so that's mean 3 hp . Breaker is 30A and is tripping after motor starts , any idea what size of breaker i have to use ? i was thinking to run new lines from panel but i don't have experience with motor . Thanks.

An A/C compressor should have a name plate with the correct minimum and maximum breaker size listed. Make sure this sucker is hooked up correctly. Correctly tapped for voltage applied.

Don't be so quick to install a larger breaker get some information first. Did this compressor work with this breaker at one time or is this a new install? You may have a loose connection at the breaker causing a trip. Put an amp meter on there an see what it drawing and check this against the name plate rating.

 

[weressl]

An A/C compressor should have a name plate with the correct minimum and maximum breaker size listed. Make sure this sucker is hooked up correctly. Correctly tapped for voltage applied.

Don't be so quick to install a larger breaker get some information first. Did this compressor work with this breaker at one time or is this a new install? You may have a loose connection at the breaker causing a trip. Put an amp meter on there an see what it drawing and check this against the name plate rating.

The breaker may also need to have an HRAC(?) rating. (Special curve breaker for compressor duty.)

 

[Smart $]

HRAC(?)

HACR (Heating, Air Conditioning, and Refrigeration)

 

[weressl]

HACR (Heating, Air Conditioning, and Refrigeration)

Yes, thank you.

Dyslexia and alzheimers, a dangewous combination.:grin: Must be all the aluminium wires I've been handling....

 

[jim dungar]

The breaker may also need to have an HRAC(?) rating. (Special curve breaker for compressor duty.)

old-wives tale: HACR does not mean a special curve.
HACR has always meant the breaker is rated for use with a "group of motors" to meet NEC requirements

Since about 1985 all UL-489 listed multi-pole breakers are tested to HACR requirements as part of the standard tests.

 

[weressl]

old-wives tale: HACR does not mean a special curve.
HACR has always meant the breaker is rated for use with a "group of motors" to meet NEC requirements

Since about 1985 all UL-489 listed multi-pole breakers are tested to HACR requirements as part of the standard tests.

Not necessarily old wives tale but the origin of the HACR requirement did include the requirement for special load profile that compressors represent. The main reason why UL required separate testing for group control of HACR was the special load characteristics that compressors represented in group control. Hence the HACR designation. Otherwise UL would just have used some designation that refered to group control. It was found that by the late 80's all breakers in production seeking UL approval did meet the requirement.

 

[jim dungar]

Not necessarily old wives tale...

Can you provide any Time Current Curve for any pre-1985 HACR breaker that is different than a pre-1985 standard breaker?

According to Square D no manufacture ever had to do anything different, other than pay for a test, to get an HACR label. The UL listing change actually occurred in the 90's:

"A great number of circuit breakers were investigated by UL using the special
HACR testing. It was found that all circuit breakers that passed the normal UL 489 tests also passed the special HACR testing without a special design."

http://ecatalog.squared.com/techlib/docdetail.cfm?oid=0900892680055a5c

 

[ohm]

I have receive a call to fix a tripping breaker for a/c compresor motor is one phase 120 v , 2.25kw so that's mean 3 hp . Breaker is 30A and is tripping after motor starts , any idea what size of breaker i have to use ? i was thinking to run new lines from panel but i don't have experience with motor . Thanks.

Are you sure this rascal runs on 120V and not 240V?

 

[LarryFine]

HACR (Heating, Air Conditioning, and Refrigeration)

They could have called it Cooling, Heating, And Refrigeration, but I can see why they wouldn't want an electrical rating spelled CHAR.

 

[Smart $]

...I can see why they wouldn't want an electrical rating spelled CHAR.

:grin::grin::grin:

 

[weressl]

Can you provide any Time Current Curve for any pre-1985 HACR breaker that is different than a pre-1985 standard breaker?

According to Square D no manufacture ever had to do anything different, other than pay for a test, to get an HACR label. The UL listing change actually occurred in the 90's:

"A great number of circuit breakers were investigated by UL using the special
HACR testing. It was found that all circuit breakers that passed the normal UL 489 tests also passed the special HACR testing without a special design."

http://ecatalog.squared.com/techlib/docdetail.cfm?oid=0900892680055a5c

Go look at the early vintage ITE breakers and the competitors'. Look at them 10 years later. Talk to some of the older UL guys.

 

[benaround]

They could have called it Cooling, Heating, And Refrigeration, but I can see why they wouldn't want an electrical rating spelled CHAR.

Or, Cooling,Heating,And Refridgeration Electrical Devices. CHARED