Buck-Boost Selection

Status
Not open for further replies.
N

Npstewart

Senior Member
Good afternoon everyone.

Im looking for a Buck-Boost Transformer for 1 HP motor because the incorrect life station motor was delivered to a site, and the correct one has a 20+ week lead time.

In the past, ive always used Schnieder Electric's calculator which would spit out a model number. The issue im having is this selector isnt functioning properly and dead-ends into a non working link. Furthermore, everything I can find online is made for 480v primary or secondary.



Parameters:
  • 1 HP single-phase Motor (~7.4 Amps)
  • Need to buck from 208v to 240v (ie. 32 Volts) to match the motor
  • Ive already asked the manufacturer if it was slash rated and they said it wasnt and they will test the voltage to warranty the pump.


    Any help is appreciated. I cant even seem to find a catalog online for this. This isnt something I get into often so I dont have many resources.
 
Are you bucking 240 down to 208 or boosting 208 up to 240?

A BB transformer is an isolation type transformer connected so that the secondary coil is placed in series with the primary.

The basic sizing rule is load amps times secondary voltage gives required transformer rating.

So if you could get a 208V : 32V 320VA transformer it could boost 208 to 240 and supply a 10A load, thus 2400VA of total load.

For your application you need to handle motor starting current, and 240V to 32V transformers are much easier to come by than 208:32. So you will probably end up using a 500 or 750VA 240:32V transformer which will give you 16 or 24A of capacity at 236V.

Jon
 
The voltage to the building is 208/3 and I was originally providing a single phase circuit (208/1) to power the pump. The problem is that the pump is explicitly labeled as 230v so I need to boost the voltage from 208 to 240v.


Yes, I calculated a 500va boost transformer but the problem is that I cant find a cutsheet or anything to download. Im just looking for a cutsheet that I can send to my client so that we can give it to the supply house to order.
 
Ask your supply house what line of transformers they represent, they could look up a part # and price it for you. Then you would know where to go to get a cut sheet if it’s still needed.
 
Npstewart said:
The voltage to the building is 208/3 and I was originally providing a single phase circuit (208/1) to power the pump. The problem is that the pump is explicitly labeled as 230v so I need to boost the voltage from 208 to 240v.


Yes, I calculated a 500va boost transformer but the problem is that I cant find a cutsheet or anything to download. Im just looking for a cutsheet that I can send to my client so that we can give it to the supply house to order.
Click to expand...
Square D #250SV46B should work
 
You will almost never be able to go from 208V to 240V, you can come close though.
A 120/240 - 16/32V transformer will only output about 28V with a 208V input, so you can get to 236V.
 
As already mentioned - a likely candidate is a 500VA unit that can be fed w/ 240VAC Primary and can supply 32VAC Secondary. As Winnie (and Jim) state above, this will give you ~ 236 volts if wired as a boost transformer and fed with 208 VAC.

A quick 2 second search around the web shows things like...

Federal Pacific K1XGF16-0.5

Hammond HPS QC50ESCB

There are lots of manufacturers and I am not advocating for either of these. However, I have purchased a small HPS buck boost ~8 years ago and the smoke has yet to come out!

1653079259268.png

Ask your supply house if they prefer ordering (and get better pricing) from a specific vendor.
 
Status
Not open for further replies.
Top