Motor Data HP?

Tim · Aug 29, 2004

I got an AO Smith AC Motor and I'm trying to figure out what the HP is. I know there is a formula for figuring this but it seems like I'm missing something when I go figuring. The owner of the motor just wants to see if it would be okay to put it on a belt disc sander.
Here is what he says is on the motor.
RPM 3450
A 23.5
HZ 60
FR 184Z
Time Cont.
Thermally Protected
Type M
LKD Amps 120
He says its a single phase motor/ 220V.
If someone can give me an estimated HP rating, or somehow the way to figure the actual rating I would appreciate it.
Thank You.
Tim

rsdoran · Aug 29, 2004

Rule of thumb makes it a 4-5(proably 5) HP motor, if single phase, the formulas can be found at http://www.patchn.com/motorformula.htm

AOSmith should have a website where you can look up that motor.

randylud · Aug 29, 2004

Curious!

With all the other data provided, there must be a name plate on that motor and if so, does AO Smith not include the HP on the name plate along with all the other stuff? Seems to me most motor people do! Just an observation.

Tim · Aug 29, 2004

Randy,
According to him, there is no other information on the name plate.

Rs,
I kind of figured it would be around the 5 horse range. I used the formula in my UGLY's hand book and just estimated the EFF. I just wondered what to do because I didn't know the Eff or pf. I seen there were ways to figure these as well, but I was always missing some kind of data about the motor and got my math a little twisted and gave up.
Thanks
Tim

rsdoran · Aug 29, 2004

I can relate to issues where the nameplate gets damaged and part can not be read. I meant to metion that 184 frame is also indicative of a 5 HP motor, the Z means that the shaft is special in some way...ie longer, bigger, may have threads etc.

FYI: Another rule of thumb pertains to the frame size, the center line shaft height from the bottom of the base is the first 2 number of the frame divided by 4...ie 184 frame divide 18 by 4 - 4.6 inches

elevmike · Aug 30, 2004

I belive the motor is 4 HP which seems to be an oddball but that's what I come up with from my cheat sheet. Should have 30 amp duel element fuses.

BTW AO Smiths website leaves a LOT to be desired.

waggs · Aug 30, 2004

motor HP

RPM 3450 23.5A

Tim,
I'd get a look at myself and see what it says for phase. 23.5 Amps would put it at 7/12 HP 3phase at 208/230. I don't mean to confuse the issue, just wondering when someone else gives you the specs...as they say, been there, done that.

Bob

elevmike · Aug 30, 2004

I have to agree with Waggs. 23.5 amps w/220 volts 3phase is dead nuts 7.5 HP. Also the fact that the rpm is 3450 also brings a LOT of suspesion about the motor being 3 phase. Ask the guy about how many wires are coming out of the motor.

Edit: The Frame (184) (open frame) also points to a 7.5 hp 3 phase motor.

waggs · Aug 30, 2004

points to a 7.5 hp 3 phase motor.

Mike,
Thanks for decyphering my 7/12ths motor...lol. God its late.

Bob

Eric Nelson · Aug 30, 2004

Glad to see everyone's in agreement, NOT!...

Single Phase - I'd guess 5 HP (but only because 4 is just weird)
Three Phase - I'd guess 7½ HP

If I were a betting man, I'd put my money on Tim's motor being 3 phase, regardless of what 'the owner' says.

beerchug

-Eric

JesperMP · Aug 30, 2004

Thermally Protected

Unless this is supposed to be thermistors or Pt100's, then it is a thermoswitch connected in series with the leads to a single-phase motor.

But 23 A seems to be quite a lot for single-phase.

elevmike · Aug 30, 2004

JesperMP said:
Unless this is supposed to be thermistors or Pt100's, then it is a thermoswitch connected in series with the leads to a single-phase motor.

??? We have quite a few 3 phase AO Smith motors (aka Centruy) with a thermoswitch. They're provided on a seperate pair, apart from the motor leads.

JesperMP · Aug 30, 2004

OK, but the wording "thermally protected" seems to mean that the motor has protection integral to itself.
Otherwise shouldnt it have been "capable of thermal protection via integral thermoswitch".
I have seen single-phase motors with a thermo-switch in series with the supply leads. But I guess that an integral bimetallic thermoswitch would never go to 23 A.

elevmike · Aug 30, 2004

Yep, name plate can be missleading. Truste me, your not the first.

rsdoran · Aug 30, 2004

The owner of the motor just wants to see if it would be okay to put it on a belt disc sander.

I made a few assumptions based on that statement. That this a home project so single phase would be what is available. My rule of thumb states 5 amps per HP at 230v 1 PH so I rounded it to 5HP.

The 184 frame could be either a 5HP or 7.5HP.

I couldnt make myself believe that people in an industrial environment would need to ask this question.

Motor Data HP?

Tim

Member

rsdoran

Lifetime Supporting Member

randylud

Member

Tim

Member

rsdoran

Lifetime Supporting Member

elevmike

Member

waggs

Member

elevmike

Member

waggs

Member

Eric Nelson

Lifetime Supporting Member + Moderator

JesperMP

Lifetime Supporting Member + Moderator

elevmike

Member

JesperMP

Lifetime Supporting Member + Moderator

elevmike

Member

rsdoran

Lifetime Supporting Member

Similar Topics