Motor efficiency calculations explained

As with most electrical concepts, this one often gets overcomplicated when it doesn't need to be.

[@orendanoisecat6128]

THANK YOU! My instructor breezed past this and I couldn't comprehend it with his explanation. THIS made it so clear. I swear RUclips is my evening class, where the REAL learning is happening

[@rcinfla9017]

Did not include power factor of motor. To know amperage input you need VA input = Power input / power factor. Typical induction motor has PF between 0.75 and 0.88 depending on percent of rated loading on motor. It is the inductive component of motor load.

[@MrJobieRossell]

I don't want to be the bear of bad news but this is wrong because you don't mention power factor.....

[@EricJohnson-yn2qv]

Can you discuss 3 phase efficiency and power factor calculations

[@technokitten2038]

Good video but isnt this a 3 phased motor? Then the formula should also include sqrt(3) and cos phi, right?

[@saifsiouf7684]

Even the single phase equation has a power factor in it

[@robertingersoll5289]

Really good videos on your site. But - Wrong power formula for input power!
If single phase P = V x I x PF
if 3 phase P = 1.73 x V x I x PF

[@abo000Saad]

What about the power factor?

[@victoryfirst2878]

The efficiency of just about anything today is BLURRED. I do not believe humanity will ever make something with super efficiency. Their is just to much pressure from the "powers that be" to keep that from ever happening.

[@hernanherrera3736]

Where did you get 746 from?

[@richiealing56]

Same question

[@paulluevano3672]

He converted power from HP to watts. 1 hp = 746 watts

[@rockrl98]

I expected motor design and load stuff, disappointing, elementary school stuff lol

[@boyetCoranesyahoocom]

we need how to calculate motor efficiency, but you are teaching how to calculate input power. y?

[@WarriorEditzfyp]

This Vid is banger

[@Shredxcam22]

Good explanation but unless your getting a motor out of a dumpster, they normally have the FLA on the nameplate.
It just goes to show why you need to pick a more efficient motor when building a system

[@سلاج]

With me his love, this engine is born electrically electrically

[@Drew-n-Denver]

This guy is great. I’ve been a JW for 25 years and am studying for a license in a new state. It’s been a bit since I’ve had to do these calculations. Thanks for the easy explanation!

[@alonsohdzf]

Great explanation about input v.s. output power. But that looks like a three phase motor, and you aren't using sqrt of 3. How so?
Thanks for posting this good content!

[@realaim3363]

I have a question pls... what size 2 pole breaker must be used on a 3HP, 115 V single phase motor? so basically we are looking for Amps. so please if you could make a video that explains a situation where you do not have e.f.f or PF or maybe u have PF and looking for e.f.f PF and EFF not given

[@rogerwitmer2659]

How much power will a 1-horsepower, 12-volt dc electric motor that is 75% efficient require? Output/Input,
1hp(746w)/.75=

[@rameshdathrampersad9216]

Hi there Great vid but i have a question. I have a motor that has no efficiency or power factor information written on the nameplate. How do i calculate input power or power factor? I see a rating of 1/2 Horse power but i think thats the output power of the motor, and other info like FLA and voltage Any help will be much appreciated. Thanks.

[@ExiledinIN]

You have to account for power factor. Power in a 3 phase motor is: P = square root (3) * Volts * Amps * Power factor. Most 3 phase motors PF is .7-.8. For single phase P = Volts * Amps * Power Factor. Power = Volts * Amps only holds true for DC powered machines.

[@astifcaulkinyeras]

True but 240V is single phase.

[@TheElectricAcademy]

I guess I should do a video with pf and efficiency?

[@trundle888]

The Electric Academy
Great videos, I’ve found several of them very helpful!!
Do you have any videos with general knowledge on motors rather than formulas? I’m challenging my red seal soon and in practice exams I’m struggling with all these random questions on motors. I can’t seem to find any good online sources to learn about motors.
Please help!
Thanks

[@TheElectricAcademy]

trundle888 I do have a few on motor connections.

[@trundle888]

The Electric Academy
Ok great, I’ll see what I can find and check them out.
Thanks

[@lax_player2527]

I might actually get my electrical ticket because of you. So glad I just found you’re channel literally 2 days before I take my exam

[@josephvargas9707]

Sorry where u get the 746 from ?

[@michaeldoran4367]

1 HP = 746 watts

[@marks7352]

We always use .75 for the EFF?

[@AutomationDnD]

Good Stuff

[@gregprice8718]

Where does the 746 come from

[@richiealing56]

Where did you get 746?

[@lax_player2527]

You just saved my life 😂

[@owss001]

THANK YOU!

[@amirhesamagah52]

😶

[@mato3353]

ily