Inverter duty motors

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mshields

mshields

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Boston, MA
I've always been under the impression that inverter duty rated motors had a service factor of 1.15. I have learned that Baldor makes inverter rated motors but that they have a service factor of 1.0.

Can anyone shed light on what the story is here. Baldor hasn't been particularly helpful in clearing up the confusion other than providing the above statement.

thanks,

Mike
 
Pure Sinusoid

Pure Sinusoid

Baldor takes the stand that their motors can handle a 1.15 SF if on a Pure Sinusoidal source - but only a 1.0 SF if the souce is not a "True" sinusoid (VFD). I am trying to buy several VFD rated motors right now & require a 1.15 - Baldor/Reliance will only quote me 1.0 on VFD. I have purchased Reliance motors in the past for VFD use that had a 1.15 SF. Most other suppliers will provide a an "oversized" frame (say next size up) for a VFD app that has more than a 2:1 turndown for cooling reasons (or an external blower). Just like when you get a K-Factor rated transformer...........it is all about heat dissapation.
 
mshields said:
I've always been under the impression that inverter duty rated motors had a service factor of 1.15. I have learned that Baldor makes inverter rated motors but that they have a service factor of 1.0.

Can anyone shed light on what the story is here. Baldor hasn't been particularly helpful in clearing up the confusion other than providing the above statement.

thanks,

Mike
Click to expand...

One has nothing to do with the other. Many models built to IEEE841 have 1.15 sf and "suitable" for inverter duty.

But let's approach it as an engineering issue; why do you think you 'need' the 1.15 sf?
 
1.15 service factor

1.15 service factor

I gather that I do not need it. If Baldor states that it is inverter rated with 1.0 service factor (which they have), that ought to do it.

It's been a bit of a sticking point because the submittal indicated that it would have a 1.15sf in accordance with our spec. The unit that arrived on site had a nameplate indicating a 1.0 sf.

They've acknowledged that mistake and the bottom line here seems to be that we should revise our spec.

Mike
 
mshields said:
I gather that I do not need it. If Baldor states that it is inverter rated with 1.0 service factor (which they have), that ought to do it.

It's been a bit of a sticking point because the submittal indicated that it would have a 1.15sf in accordance with our spec. The unit that arrived on site had a nameplate indicating a 1.0 sf.

They've acknowledged that mistake and the bottom line here seems to be that we should revise our spec.

Mike
Click to expand...

1.15 sf DOES have its use. It has a value therefore if your supplier did not meet the specification (s)he owes you money. There are other motors that would have met the specification so unless your spec is limited to Baldor, then you were shortchanged.

Baldor is famous for targeting "price-buyers" and of course you get what you pay for. I would have not touched a Baldor motor for years, because our service requirements were high and even though they have met those on paper, but not in practice. Now I am start looking at them again, especially since they now own Reliance also.
 
weressl said:
Baldor is famous for targeting "price-buyers" and of course you get what you pay for. I would have not touched a Baldor motor for years, because our service requirements were high and even though they have met those on paper, but not in practice. Now I am start looking at them again, especially since they now own Reliance also.
Click to expand...


Since you mentioned Baldor, what do you think about Leeson motors?
 
weressl said:
Baldor is famous for targeting "price-buyers" and of course you get what you pay for. I would have not touched a Baldor motor for years, because our service requirements were high and even though they have met those on paper, but not in practice. Now I am start looking at them again, especially since they now own Reliance also.
Click to expand...


Since you mentioned Baldor, what do you think about Leeson motors quality wise?
 
For my money the best motor on the market is SEW. I have used them for several years in harsh industrial applications and they perform very well.
 
We use SEW on our rag machines. They are pretty good, but kinda hard to trouble shoot. They have a DC rectifier and a relay built in, for the brake, so you can't just check it at the starter for a short. Due to the design of the rag machines it is very hard (and nasty) to get to the pecker head. I also don't like the terminal block, made of ceramic, I think. It breaks very often.
 
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