# Is a PM Generators output greater than an A/C motors input?

• imac567
In summary, the conversation discusses the possibility of powering a permanent magnet generator with an A/C motor and whether the output watts of the generator would be greater than the input wattage needed to run the motor. The individual is seeking clarification on whether the drive torque of a PM generator is significantly less than a conventional generator. The expert concludes that this would violate the law of conservation of energy and advises against it.
imac567
Hi, If I powered a permanent magnet generator like one found in a wind turbine, with let's say with a 1/2 hp A/C motor for example and directly coupled them together or used a gear reducer to increase the torque and rpm's, would the output watts created by the generator be greater than the wattage needed to run the input motor?
I'm asking this because what I've heard is that a pm generators required drive torque under load is much less than a conventional generator. I'm no electrical engineer by any means but I am and industrial mechanic specializing in rotating assemblies and and other boiler plant equipment and operations. Any help would be greatly appreciated.

Thank you, Mark

No never you'd be violating the law of conservation of energy.

## 1. What is a PM generator and how does it differ from an A/C motor?

A PM generator, or permanent magnet generator, is a type of electrical generator that produces electricity by converting mechanical energy into electrical energy through the use of permanent magnets. On the other hand, an A/C motor is a type of electrical motor that uses alternating current (A/C) to convert electrical energy into mechanical energy.

## 2. Is the output of a PM generator greater than the input of an A/C motor?

In most cases, yes. PM generators are typically more efficient than A/C motors, meaning they can produce more electrical energy for a given amount of mechanical energy input. Additionally, PM generators do not have the same energy losses that A/C motors do, further contributing to their higher output.

## 3. What factors affect the output of a PM generator and input of an A/C motor?

The output of a PM generator can be affected by factors such as the strength and orientation of the permanent magnets, the speed at which the generator is rotating, and the design and quality of the generator. The input of an A/C motor can be affected by factors such as the frequency and voltage of the A/C power supply, the design and quality of the motor, and the load placed on the motor.

## 4. Are there any situations where the output of a PM generator may be less than the input of an A/C motor?

It is possible for the output of a PM generator to be less than the input of an A/C motor in certain scenarios. For example, if the PM generator is not properly designed or is operating at a low speed, it may not be able to produce enough electrical energy to match the input of the A/C motor. Additionally, if the A/C motor is operating at a low load, it may require less input energy, resulting in a higher input than the output of the PM generator.

## 5. How is the output of a PM generator and the input of an A/C motor measured?

The output of a PM generator is typically measured in terms of electrical power, usually in watts (W) or kilowatts (kW). The input of an A/C motor is typically measured in terms of electrical current, usually in amps (A) or kilowatts (kW). Both can also be measured in terms of their respective energy units, such as joules (J) or watt-hours (Wh).

Replies
9
Views
1K
Replies
3
Views
1K
Replies
1
Views
1K
Replies
2
Views
6K
Replies
42
Views
4K
Replies
12
Views
6K
Replies
1
Views
933
Replies
3
Views
3K
Replies
1
Views
2K
Replies
21
Views
8K