# Fraction size NEMA starters



## 460 Delta (May 9, 2018)

Does anyone else use or order Siemens(Furnas) in between size starters? I have bought several 1 3/4 NEMA for air compressors to replace IEC stuff which I’m none to fond of. I do realize that Furnas was making things motor size specific sorta like IEC but more NEMA robust and rebuildable. 
Curious to hear your thoughts.


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## MDShunk (Jan 7, 2007)

Short answer, no. Not everyone makes them, and they're more suited to retrofit applications where spaces is among the primary concerns. I don't really think the fraction sizes are actually NEMA sizes anyhow. I think they're extrapolated from standard NEMA sizes. Best of luck getting a renewal kit 20 years from now.


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## Wirenuting (Sep 12, 2010)

Only place I've seen and ordered them were in Furnas MCC's that had the non-nema sized international buckets. Those PITA buckets were everything was shoved in sideways.


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## 460 Delta (May 9, 2018)

Getting replacement parts for a Citation series Cutler Hammer is a pain also. Anything 20 years old might as well be 100. 709 series Allen Bradley is doable but you’ll have to order and wait. 
Unitrol CH had the NEMA 2 size sideways so that doesn’t really bother me, I’m used to that setup. 
Yeah I know it’s a odd made up size system,but it does work for retrofit work, but I make my living keeping old plants operational batching concrete. 
Just seeing if yet again I’m the Lone Ranger using Furnas sizes.


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## Wirenuting (Sep 12, 2010)

460 Delta said:


> Getting replacement parts for a Citation series Cutler Hammer is a pain also. Anything 20 years old might as well be 100. 709 series Allen Bradley is doable but you’ll have to order and wait.
> Unitrol CH had the NEMA 2 size sideways so that doesn’t really bother me, I’m used to that setup.
> Yeah I know it’s a odd made up size system,but it does work for retrofit work, but I make my living keeping old plants operational batching concrete.
> Just seeing if yet again I’m the Lone Ranger using Furnas sizes.


Here is were I last worked on the FPE MCC’s.
We installed all new Furnac MCC’s and 9 years later this was the result.


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## 460 Delta (May 9, 2018)

All I’m doing is buying time, I’ve long since made peace with that. Nothing lasts forever. 
Good enough is just that, good enough.


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## micromind (Aug 11, 2007)

The only odd size starter I use is an Allen Bradley 609 XOX. This is a NEMA manual starter that is rated for 5HP 240 volts single phase. 

It's listed as a size 1P. The contact ratings for a size 1 is 27 amps, 1P is 36 amps and 2 is 45 amps.


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## JRaef (Mar 23, 2009)

Furnas made up their own rules on those "tweener" sizes, it was never officially a NEMA concept. They were the only ones to do so for that reason, and they did it because they had to have a "gimmick" in order to try to stay relevant in a world dominated by bigger players. Ultimately it didn't matter and they were gobbled up by Siemens, but Siemens decided, at least for the time being, to maintain the practice.

The entire concept of NEMA starter sizing was to take the decision making process on selecting motor starters out of the hands of expensive engineers in ivory towers, and allow front-line electricians to pick the parts quickly and easily without having to worry if it would survive or not, thus getting the production line up and running again. So a NEMA designed starter was expected to take the worst thing you could throw at it without much thought to it. If your machine was NOT the worst thing, so be it, you just had a bullet-proof controller.

IEC starters were designed by (mostly) the Germans after WWII when our Marshall Plan paid for a lot of them to go to college and get engineering degrees, rather than learn trades. In the previous two wars tradesmen were considered "expendable" as soldiers, so they were cannon fodder. Their children who could take advantage of the Marshall Plan didn't want to be cannon fodder in the next war, so they became engineers. That resulted in a glut of engineers; more than qualified tradesmen, so engineers were cheap, tradesmen like electricians were actually more rare. Then also because materials were MUCH more expensive after the war, components like starters were designed to use as little material as possible, so they had to be "rationalized" into each and every application by an engineer studying EXACTLY how many times it would operate, how long the rest period is between operations, the power factor and the time it connected, the nature of the load and the expected lifetime. There was also zero thought of "rebuilding" them, because that was a pointless exercise, since there were no tradesmen available to do it.

Furnas' tweener sizes were just their gimmick, it was actually counter-intuitive to the overall NEMA starter sizing philosophy.


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## 460 Delta (May 9, 2018)

I don't agree that split sizes are counter intuitive ,they state on the 1 3/4 size that it is rated for 10 hp on 208-230 and 15hp on 460. That seems pretty NEMA to me. The slight size advantage is a plus when tossing a IEC junker and shoe horning in a replacement. 
I will agree that they will likely be discontinued in the future, the old guy at the supply house asked me to repeat myself when I ordered the first one, he said that he hadn't thought about or sold one in years.


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