Input torque and speed for 1 KW generator.

[suyog21]

How to calculate input torque and speed, i want to generate 1 kw of power. I am design a pneumatic motor to drive generator.

and also if speed of input pneumatic motor varies +-300rpm

Suyog Patil
CAD Enginer
NX 7.5. 8, 8.5 9, 10 TC-9

 

[Skogsgurra]

Use the fact that electric power is equal to mechanical power. Then convert to SI and apply whatever efficiency numbers are valid for the generator type. DC, asynchronous, synchronous or PM type. Below a small DC generator with an assumed efficiency equal to 0.8 and nominal speed 1500 RPM:

n is, of course, 1500 RPM. But you need to use the rad/s speed to find torque. So w = 1500*2*PI/60=157 rad/s

Torque needed is then power/w=1000/157=6.37 Nm

If efficiency is 80 percent, you need to increase torque to 6.37/0.80=7.96, say 8.0 Nm

To guarantee full output at lowest speed you need to use 1500 - 300 RPM. That will increase needed torque correspondingly.

w=126 rad/s torque at 100 % efficiency = 7.96 Nm and, at 80 %, 7,96/0.80=9.95, which is very close to 10 Nm.

The voltage regulation is not your problem, but should not be forgotten. It should also be noted that a PM generator plus an inverter probably is the best way to produce a stable AC or three-phase system from the variable generator output. If your output shall be DC - well, there are several ways to skin that cat also.



Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[dogzzz]

I guess you deal with 50 HZ .
So ,4 pole , 1500 RPM motor , 1250 KW motor shall generate a torque of 6631 N-m torque and will be suited for generating a 1000 eKW.

+/- 300 RPM shall mean that the generator frequency shall be 40HZ @ 1200 RPM (-300 RPM)( thus your generator breaker may trip due to under frequency ) and shall be 60 HZ(+300 RPM) @ 1800 RPM. This time generator breaker may trip due to over frequency.

 

[MintJulep]

Using air to make electricity has got to be the least efficient way possible.

How are you making air?

Get the electricity closer to the source of power.

 

[waross]

This is a 1 kW generator, not a 1000 kW generator. A breaker with a frequency trip is rare at that size.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dogzzz]

Yeah Bill you seems to be correct....I always dealt with megawatts....but wondering this 1 KW generator may spoil the equipments it is feeding to in case no frequency protection.

 

[waross]

This application may work best with wind turbine type technology. produce DC or rectify to DC and then invert to AC at the desired frequency.

Bill
--------------------
"Why not the best?"
Jimmy Carter