Issues with using too big motor

[Krokodil]

I've got a little project that will require approx 350W motor. I can find a good 750W motor at a good price. This is for single phas 220V.

My electrical engineer friend says there is no issues using too big motor. It will just be inefficient and use more electricity.

What are the drawbacks in practise of using a overkill motor?

 

[FluxCore]

I've got a little project that will require approx 350W motor. I can find a good 750W motor at a good price. This is for single phas 220V.

My electrical engineer friend says there is no issues using too big motor. It will just be inefficient and use more electricity.

What are the drawbacks in practise of using a overkill motor?

Hotrodder's Motto sez, "If a little bit is just right, too much is mobetter"

That said, as long as all other requirements are met (RPM, fits were intended), then you need only to design power supply, switching and controls to support higher starting and run currents....You can expect to pay more to run it, but maybe later you can swap in a 350 when you find one scrapped or free.

 

[Krokodil]

Ok, that sound good. It is not going to run for more than 2 hour per week. No harm done to the planet.

 

[nehog]

...
My electrical engineer friend says there is no issues using too big motor. It will just be inefficient and use more electricity.
...

I can point out scenarios where the larger motor would use less power than the smaller! (Mostly due to poor design, however.)

 

[FluxCore]

Yup, it will use MORE electricity per work performed, but in reality, the extra cost will be minor...we are only talking a 1 HP motor here that will be used little...LOL, it should last forever

AC induction motors of recent era are perhaps 85% efficient, and then only when loaded near rated load....A guy could argue a 2X motor is 2X less efficient, and his argument would be valid if designing an install where there would be multiple high HP motors involved in a 24/7 process..but in this case, too much is ok

My self, I like haveing more available than needed...After all, who said you have to put it all the way in?

 

[EOC_Jason]

As long as the rest of the electrical components can support the larger motor, there is really no harm except you will be using a little more power.

 

[Krokodil]

Thanks for the confirmation guys! I ordered the motor today. Will probably pick it up on Thursday.

There is an interesting joke going around on the mines here that the design requirements for most of the mine equipment are: "big x strong x heavy"

 

[DekeT]

My electrical engineer friend says there is no issues using too big motor. It will just be inefficient and use more electricity.

The drawbacks are that it will be a little inefficient and use more electricity. I hope your electrical engineer friend does not read the GJ.

 

[Krokodil]

Oversized motors are a swore point for most engineers. Doing research for this project I read somewhere that something like 50%+ of all industrial application motors are oversized.

 

[EOC_Jason]

Unfortunately these days you have to "oversize" components if you want them to last any reasonable amount of time.

 

[George in Rancho Cordova]

Just don't load down the machine using all the power available from the motor. Something will break.

 

[rsanter]

What is the motor on?
It can cause a safety issue where the smaller motor will stall the bigger one will hurt you

Bob

 

[Krokodil]

It will be used on n rotary type brass case tumbler with ss media and water. Two shafts on pillow blocks will be driven with the drum on top.