AC Automatic Voltage Regulator

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eng.moh.4u

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Location
Egypt
I need to determine KVA needed by Automatic Voltage Regulator for A/C and details as below:

  • Cooling Capacity= 13500 BTU
  • Voltage = 115 V , 60 HZ
  • COMP RLA = 63 (compressor rated load amps)
  • COMP LRA = 12 (compressor locked rotor amps

I need Automatic Voltage Regulator cause I have input 220V 60Hz
 
Saturn_Europa

Saturn_Europa

Senior Member
Location
Fishing Industry
Occupation
Electrician Limited License NC
eng.moh.4u said:
I need to determine KVA needed by Automatic Voltage Regulator for A/C and details as below:

  • Cooling Capacity= 13500 BTU
  • Voltage = 115 V , 60 HZ
  • COMP RLA = 63 (compressor rated load amps)
  • COMP LRA = 12 (compressor locked rotor amps

I need Automatic Voltage Regulator cause I have input 220V 60Hz
Click to expand...

Do you have your amperage ratings reversed?

LRA are usually always higher than RLA
 
Besoeker

Besoeker

Senior Member
Location
UK
zbang said:
A simple step-down transformer is the usual way to go for something like this.
Click to expand...
Not a very big one at that if the normal running load is 6A.
A a lot simpler than an AVR.
Unless there's something we haven't been told.............
 
Besoeker

Besoeker

Senior Member
Location
UK
Sahib said:
Multiply current rla and voltage. It is about 1.2 KVA. Go for 2KVA transformer to account for voltage drop during LRA
Click to expand...
It's 1.4kVA at RLA. The minimum circuit amperage is 20A with a heater. MCA is not a term I would use but I assume it is the minimum design rating for the conductors etc. If so (others feel free to correct me) I think would base the transformer rating on that. So the next standard up from 2300kVA.
A better idea might be to back to the supplier of the aircon equipment if that's possible and ask for their recommendation.
 
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topgone

Senior Member
Besoeker2 said:
It's 1.4kVA at RLA. The minimum circuit amperage is 20A with a heater. MCA is not a term I would use but I assume it is the minimum design rating for the conductors etc. If so (others feel free to correct me) I think would base the transformer rating on that. So the next standard up from 2300kVA.
A better idea might be to back to the supplier of the aircon equipment if that's possible and ask for their recommendation.
Click to expand...

Agree. The equipment MCA is 18.6A and you will need more than 2.139kVA for this feed. IMO the next standard up is 3 kVA.
 
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Ingenieur

Senior Member
Location
Earth
Looks like only comp or htg can run, not both
htg is larger
13.2 + 3.4 = 16.6 (mca 1.25 x 13.2 + 3.4 ~20)
115 x 16.6 = 1.9 kva, 2.5 should be fine
 
Besoeker

Besoeker

Senior Member
Location
UK
Ingenieur said:
Looks like only comp or htg can run, not both
htg is larger
13.2 + 3.4 = 16.6 (mca 1.25 x 13.2 + 3.4 ~20)
115 x 16.6 = 1.9 kva, 2.5 should be fine
Click to expand...
Then why would there be a higher MCA for the one with the heater?
Wouldn't you rate it to the MCA?
 
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Ingenieur

Senior Member
Location
Earth
Besoeker2 said:
Then why would there be a higher MCA for the one with the heater?
Wouldn't you rate it to the MCA?
Click to expand...

the actual load is ~ 16.6 A
the conductor ampacity is ~1.25 times that (1.25 x largest load plus the fan)
I'd size for the actual load of 16.6
1.9 kva
a 2.5 gives 30% headroom or an operating point of 76%
 
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