150Hp Motor

Not likely. The general rule of thumb is that you need for the generator kVA to be 1.5 - 2x the motor HP (single motor application). So that makes it 225kVA minimum, i.e. for an uncoupled motor or something that needs little torque to start (pump, fan) but it also depends on the load. You may need more.

When an electrical motor's rated power is given by Hp, then you have to know that this is the shaft (output) power, on the other hand, if the power of a motor is given by Kw then it is the input power.

As your motor's power is given by Hp, divide it by the efficiency to know the required input power to the motor (i.e. the output power from the generator). However, the efficiency of electrical motor is almost around 90%.

For DOL (direct on line motors), the answer of JRaef is fair. In case of soft starter, your generator can easily run that 150 Hp motor whatever the mechanical load is. That is, even if the generator is pre-loaded with the difference between full-load and motor rated power.

Good Luck... Samak

The rated motor power is not necessarily equal to the real consumed power. If your motor does not use the whole rated power your generator might be able to drive it.

This is a good point. I have surveyed several electric motors recently in the 50 to 200 HP range that based on the amperage were operating far below FLA and rated HP. Do you have any similar pumps operating in a plant that you could effectively use their information to truly project actual required running HP, running amps and start up amps? Implementing something like this requires extra caution and safeguards though. If you haven't bought the motor yet maybe you don't really need a 200 HP motor. Is it a case where the pump manufacturer shows that to use ALL the pumps capacity 200 HP is required? These are just some of my random thoughts.

Is this a continuous duty pump? Constant speed or variable speed? Type of pump, positive displacement, vane, etc? Starting head pressure or starting torque? Location, pad mounted, down-the-hole, etc? It would be good to know all the facets of the operation to give the best advice. If it is continuous duty pad mounted pump, why not just use a direct drive from the power source (engine, steam turbine, etc) to the pump?

It takes a great deal more power to start the motor bring up the load than to pull the load at rated power.

If you can decouple the load with a clutch, have a small motor to spin up the big motor then turn the electriecty on. Then slowly put the load on the motor you can use a lot smaller generator but you need a lot smarter operator.

A 150 hp 3 phase motor is abut 2.5 feet in diameter and 3.5 feet long and draw a lot of current on start up. I don't know how many horse power the wind tunnel at Texas A&M has but it used to have to give the power company 3 day notice when it would start up and could only start between 3:00 and 4:00 am in the morning.

Gordon

Wind tunnels ar in the neighborhood of 5000 to 15000HP, a little bit different that what we were discussing.

hi everyone,

i'm a layman on this area, but as i know 1hp nearly equals 746w, so 150hp equals about 111kW, it should be fine using this generator.

Hi everyone,

One KW is exactly 1.36 HP. This mean that 150HP is equal to around 110KW.

Maybe I this will help you to solve the problem ;)