# Increasing the efficiency of a simple electric motor?

• CosB
In summary, the conversation discusses the design and efficiency of a simple electric motor using a D cell battery, copper wire loop, and a magnet. The individual has found a way to make the wire loop spin using current and a magnet, but is looking for a design that allows for current to flow in both directions, eliminating the reliance on momentum. Suggestions are made to use a homopolar motor or a brushed motor with multiple coils, but the individual is limited to using a single variable to control the magnetic force. The conversation ends with the suggestion to research commutators for further understanding of motor design.
CosB
Okay, so I have a simple D cell battery, enamel coated copper wire loop and a magnet. I can easily get the copper wire loop to spin if I scratch away part of the enamel (that side which touches the stand) off the ends of the wire, run current through a stand, and position the magnet at just the right position.

Here's the problem...

When I run a simple electric motor in this fashion, I'm relying on the momentum of the wire to spin back around, hit the magnets magnetic field, then be spun again (which is not efficient)

What I need to be able to set up is a simple electric motor like this that allows current to run BOTH ways through the copper wire loop, basically spinning it constantly without having to rely on momentum to spin it back around. I'm having a super hard time figuring out a plan for this pand just wanted to see if anyone could help me out.

Why don't you build a homopolar motor like this?

Last edited by a moderator:
Bob S said:
Why don't you build a homopolar motor like this?

I actually would have definitely preferred to build a motor like that, and I actually wanted too, except I'm required for my class to keep the typical simple motor design (much like this one http://www.youtube.com/watch?v=oRSU4FnUSrA&feature=related).

The homopolar design does have one characteristic that I do need, and that's the constant movement of the copper wire without relying on momentum. I just need to be able to take momentum out of the design and then id be set.

Last edited by a moderator:
With brushed motor, you kind of have to rely on inertia to carry the anchor through at least part of the rotation. You can improve the efficiency by having multiple coils. Typical cheap DC motors have 3 coils with 2 brushes. It's a pretty efficient design.

To get it even more efficient, you have to go brushless, but that involves either AC current or complex electronic controllers.

K^2 said:
With brushed motor, you kind of have to rely on inertia to carry the anchor through at least part of the rotation. You can improve the efficiency by having multiple coils. Typical cheap DC motors have 3 coils with 2 brushes. It's a pretty efficient design.

To get it even more efficient, you have to go brushless, but that involves either AC current or complex electronic controllers.

Gotcha! Ill stick to the more simple "cheap DC motors" haha. Thank you for the help!

Do you mean the loop connects to the battery and the whole thing suspended in air free to rotate. Then you put a magnet close by and try to make it rotate?

This will not work as motor works by repulsion of the two magnets ( one permanent magnet and one from the loop). Problem is once the loop turn and the pole change and become attracted to each other, then it stop and stuck! To make turn continuously, you have to change the direction of the current to keep the two magnets repel each other. That is why motor has the thingy that I think called stratem or something that can switch current direction when turning.

NascentOxygen and Yungman, that you for replying! I have an update to my question, so I don't think a picture will be needed for this.

My professor has told me that basically I can only control one variable of the Magnetic Force equation= qvBsin. I can't really control the B or sin of theta, but what I can do is control the velocity. My idea was just to make the loop smaller. Therefore, a smaller loop= smaller radius. A smaller radius equals a greater centripetal force which is equal to the Magnetic Force. Does that make any since or am I just loosing my mind?

As for what exactly I am working with, here is a general picture of the setup. My idea was just to make a tiny tiny loop to increase the efficiency, since of a larger one.

#### Attachments

• Elec_img136.jpg
27.7 KB · Views: 1,013

CosB said:
As for what exactly I am working with, here is a general picture of the setup. My idea was just to make a tiny tiny loop to increase the efficiency, since of a larger one.

I think your professor was hinting at the fact that you need a circuit that will make the current flow in two directions - but one direction at a time. This will be necessary if you want the coil to keep rotating.
I suggest you search for images of simple electric motors and make sure that you search, using the word "commutator" (the name of the device you need to use and understand about).
Pictures you find will show you the best place to locate your permanent magnet and how to arrange for the coil to keep rotating.

sophiecentaur said:
I think your professor was hinting at the fact that you need a circuit that will make the current flow in two directions - but one direction at a time. This will be necessary if you want the coil to keep rotating.
I suggest you search for images of simple electric motors and make sure that you search, using the word "commutator" (the name of the device you need to use and understand about).
Pictures you find will show you the best place to locate your permanent magnet and how to arrange for the coil to keep rotating.

So sophicentaur, what if all have is just the wire, magnet, and battery. Is there a way to get a somewhat efficient electric motor out of this besides the basic "scratch the enamel off one side of the axles, connect the current, and position the magnet". Is there somethign i can do to the actual design of the wire loop ( like make it smaller, add tiny loops around a larger loop)?

Until you have found out about a commutator, there's no point in looking further into motor design.

## 1. How can the efficiency of a simple electric motor be increased?

There are several ways to increase the efficiency of a simple electric motor. One way is to use high-quality materials for the motor's components, such as copper wire for the coils and powerful magnets for the rotor. Another way is to reduce friction by using ball bearings or other low-friction materials. Additionally, keeping the motor well-lubricated and properly maintained can also improve its efficiency.

## 2. Can the size of the motor affect its efficiency?

Yes, the size of the motor can impact its efficiency. Generally, larger motors tend to be more efficient because they can generate more torque without using as much energy. However, this also depends on the specific design and construction of the motor.

## 3. Is it possible to improve the efficiency of an old electric motor?

Yes, it is possible to improve the efficiency of an old electric motor. This can be done by replacing worn out or damaged components, such as the bearings or coils, with new ones. Additionally, regular maintenance and cleaning can also help improve the motor's efficiency.

## 4. How can the power source affect the efficiency of an electric motor?

The power source can greatly affect the efficiency of an electric motor. Using a higher voltage power source can increase the motor's efficiency, as it allows for faster rotation and less energy loss. It is also important to use a power source with the correct voltage and frequency for the specific motor, as using the wrong power source can decrease efficiency and potentially damage the motor.

## 5. Are there any ways to increase the efficiency of a simple electric motor without modifying its design?

Yes, there are some ways to increase the efficiency of a simple electric motor without changing its design. These include keeping the motor clean and free of dust and debris, using a power source with the correct voltage and frequency, and ensuring proper lubrication of moving parts. Additionally, reducing the load on the motor by using gears or belts can also improve its efficiency.

Replies
2
Views
1K
Replies
23
Views
3K
Replies
4
Views
1K
Replies
9
Views
2K
Replies
3
Views
2K
Replies
3
Views
2K
Replies
8
Views
1K
Replies
7
Views
6K
Replies
25
Views
4K
Replies
3
Views
1K