Kv to HP Calculation

Yikes!

One kilovolt (1 kV) per horsepower certainly doesn't sound right! Are you sure you heard him correctly or did he say it incorrectly?

In any case, 1 kV/hp has gotta be wrong!

Now if you mean 1 kilowatt (1 kW) for 1 hp, I guess I can calm down.

Considering that transformers are sized in kVA (not kV), I'll assume that's what you meant.

Then in that case, 1kVA per HP is probably not going to work to start the motor unless you have a VFD controlling it or you are willing to risk a severe voltage drop during starting, which may interfere with it being successful. Starting power rule of thumb is that the transformer kVA must be at least 2.5 x HP if starting Across-the-Line (DOL), or 1.5 x HP if using a Reduced Voltage starter such as an autotransformer or soft starter. But those are just best guesses, you really need to commission a Transient Motor Starting analysis that takes all of the factors into consideration to be sure.

Please consult with an Electrical Engineer locally.

hello! you are trying to relate two different things.KV is the unit for voltage .HP is for power and HP can be converted to KW and KVA.a 100 hp motor is 75kw motor.It will run on a 440Volts or 0.44kv voltage applied to it. May be a 200KVA transformer will be supplying this power.Hope now u get it.

i have a motor with 7 hp capacity now i want to run this when we have a power cut so what is the best way to do that wheather to have a generator or UPS if i had to us UPS what should be its capacity for me power is free so UPS will be better but i dont know what capacity to use

To use a UPS, you must also determine how long you want to run it with no power, because the battery life is finite, compared to a generator that can have fuel added indefinitely. In both cases, you must also decide if it will be necessary to START the motor with no utility power or if you need to just KEEP it running if it already was. If Starting power is necessary, a UPS kVA would need to be at lease 2.5X the motor HP size (not the load required HP), so your motor (most likely 7.5HP because nobody makes a 7HP motor) will require a 20kVA UPS at a minimum. Generators that small are usually sized in kW anyway, so if you convert the 7.5HP to kW (.746W/HP) you get 5.6kW. But generators have what is called a "reserve capacity" for starting motors, , so you may be able to start it with a 10kW generator.

The generator would cost you roughly 1/3 the price of a UPS with a battery capacity that would run your motor for maybe 20 minutes.

Go to this site u will find how much kva required http://www.dieselserviceandsupply.com/Power_Calculator.aspx