3 phase high leg

[amazing electric]

Are all 3 phase ac units work with 3 phase high leg?

 

[nakulak]

no

you need to read the manufacturer's literature on your equipment to determine if your power is suitable for the equipment

 

[don_resqcapt19]

I am not aware of any 3 phase equipment that cannot be used with a high leg delta system, assuming that the voltage rating of the equipment is 240 volts. There are often restrictions as to what terminal you connect the high leg to.
Don

 

[bphgravity]

As stated by the two above posts, this is a listing and labeling issue. Check the manufactuer's instructions and any other markings or nameplate information provided on the speicific unit in question.

 

[220/221]

All 3 phase units I have seen worked 208 or 240.


I haven't seen ALL units though, only a couple hundred.

 

[frenchelectrican]

The only thing you have to becarefull when you hook them up with delta system you have to be well aware with wildleg because some of them have control transformer that screw it up.

i know one unit it did happen sometime back someone replace the control transformer and did not relized it was on wild leg and blew the control transfomer.

I will echo other guy's comments check the termation and phase squecne.

Merci, Marc

 

[amazing electric]

Thank you guys for your help, the ac units do spec 208-230v on the name plate, i ll check for control transformer voltage.

 

[220/221]

On the units I have come across I find the leg that goes ONLY to the compressor and put the high leg there. The controls are generally 208/240v and the fan motors are generally single phase. In my experience, in the bigger units (over 5 ton) the fans may also be 3 phase.

 

[jrannis]

If you are connecting the condensor I would doubt you would have any risk. Phase to phase it would never know.
The risk would be in the AHU due to the controls.
I havent seen units using 120v controls anymore.
But it would be best to check.

 

[brantmacga]

Thank you guys for your help, the ac units do spec 208-230v on the name plate, i ll check for control transformer voltage.

i don't mean to sound rude, but are you sure this a 3 phase unit?

 

[e57]

Many will take delta or wye (sounds like wye only....) - yeah check that control transformer location put the high leg in the wrong place and poof!

 

[amazing electric]

Yes it is a 3 phase unit, 5 ton, 30A

 

[infinity]

Many will take delta or wye (sounds like wye only....) - yeah check that control transformer location put the high leg in the wrong place and poof!

Could you explain how that works on a 4 wire Delta system with a three phase supply?

 

[brantmacga]

Yes it is a 3 phase unit, 5 ton, 30A

okay. only reason i asked is because single-phase units have the same '208-230v' nameplate rating which is saying its okay to put it on a wye system.