# Wire insulation type for 400Hz



## Bird dog (Oct 27, 2015)

FWIW...
http://www.ecmweb.com/basics/basics-400-hz-power-systems
https://www.google.com/search?q=400hz+building+wire&ie=utf-8&oe=utf-8&client=firefox-b-1-ab
http://forums.mikeholt.com/showthread.php?t=150365


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## Southeast Power (Jan 18, 2009)

I remember getting crosslinked polyethylene,
Something like this and it seemed oversized for what we were using it for.
Like this:
https://www.servicewire.com/Products/SPLEX.htm


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## frenchelectrican (Mar 15, 2007)

What voltage at 400 *HZ* ?? 

AFAIK there is about 5 type of conductors insluations that is used with 400 HZ system but I have to find my listing. 

The GPU ( Ground power unit ) typically use the DLO cable. ( most run at 208Y120 400 HZ )

For aircraft there is a specfic type of conductors it have to be used inside the aircraft.


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## MDShunk (Jan 7, 2007)

Just 115 volts.


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## Southeast Power (Jan 18, 2009)

MDShunk said:


> Just 115 volts.


Use 1000volt rated THWN. It's very easy to source


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## paulengr (Oct 8, 2017)

The problem with 400 Hz is the skin effect...most of the current flows only in the outer edges so the ampacity is lower and voltage drop higher so conductor size is much higher than you’d expect.


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## MDShunk (Jan 7, 2007)

paulengr said:


> The problem with 400 Hz is the skin effect...most of the current flows only in the outer edges so the ampacity is lower and voltage drop higher so conductor size is much higher than you’d expect.
> 
> 
> Sent from my iPhone using Tapatalk


I know. That's sorta why overclocking a VFD with ordinary THHN pops holes in it from time to time, I suppose.


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## MTW (Aug 28, 2013)

Overclocking?


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## MDShunk (Jan 7, 2007)

MTW said:


> Overclocking?


Just a made up word some people use for running a VFD at greater than 60Hz. Or, in other words, making up for engineering mistakes by running a VFD at, say, 120Hz.


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## Bird dog (Oct 27, 2015)

It may come from the computer world...
Simply put, *overclocking* means setting your CPU and memory to run at speeds higher than their official speed grade. Almost all processors ship with a speed rating. For example, an Intel Core i7 860 runs at 2.80GHz out of the box. *Overclocking* a Core i7 860 means pushing it to a clock speed higher than 2.80GHz.

https://www.pcworld.com/article/198882/overclocking_for_newbies.html


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## MDShunk (Jan 7, 2007)

Yeah, you're technically not "overclocking" the VFD, since many are rated up to 400Hz, but you most typically see them operating in the 0-60Hz range. I guess that's why people sometimes call running a VFD at greater than 60Hz "overclocking". In reality, I guess you're overclocking the motor. Few are rated to go over nameplate frequency, but it's pretty darned common in industry to run the motor at _whatever_ to get the desired results. (90Hz and 120Hz being pretty common max frequencies) The trade literature might suggest this is hard on motors (and it probably is), but my personal experience is that it doesn't shorten their life substantially enough to make re-engineering of the original "mistake" cost effective. Bearings take the hit first.


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## Southeast Power (Jan 18, 2009)

Bird dog said:


> It may come from the computer world...
> Simply put, *overclocking* means setting your CPU and memory to run at speeds higher than their official speed grade. Almost all processors ship with a speed rating. For example, an Intel Core i7 860 runs at 2.80GHz out of the box. *Overclocking* a Core i7 860 means pushing it to a clock speed higher than 2.80GHz.
> 
> https://www.pcworld.com/article/198882/overclocking_for_newbies.html


Are you staying at Teslas house by chance?? :smile:


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## Bird dog (Oct 27, 2015)

Southeast Power said:


> Are you staying at Teslas house by chance?? :smile:


I am & his wife told me how much she loves her Prius. :wink:


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## Navyguy (Mar 15, 2010)

On the ships we used anything that was XLPE rated with a non-ferrous casing such as brass braiding or aluminum casing, etc. Same insulation that is used on DC systems. Supposedly it prevents this thing called electroendosmosis; toobig of a word for me... LOL

I have only see 400 cycle on radar and navigation systems. I suspect it would have also been used on any type of sonar and weapons systems, but I don' have any specific knowledge of that.

Cheers
John


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## pudge565 (Dec 8, 2007)

MDShunk said:


> Yeah, you're technically not "overclocking" the VFD, since many are rated up to 400Hz, but you most typically see them operating in the 0-60Hz range. I guess that's why people sometimes call running a VFD at greater than 60Hz "overclocking". In reality, I guess you're overclocking the motor. Few are rated to go over nameplate frequency, but it's pretty darned common in industry to run the motor at _whatever_ to get the desired results. (90Hz and 120Hz being pretty common max frequencies) The trade literature might suggest this is hard on motors (and it probably is), but my personal experience is that it doesn't shorten their life substantially enough to make re-engineering of the original "mistake" cost effective. Bearings take the hit first.



The programming and controls techs at the one facility I worked at hated running drives over 120 Hz. Unfortunately, the powers that be refused to change the gear boxes to provide the desired speeds so 120 Hz they went...


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## Forge Boyz (Nov 7, 2014)

I wired a hammermill that had a powered feeder on it. It was supposed to be matched to the capacity of the hammermill, but the gearing is wrong. Running at almost 120hz it can only run the mill at about 70%. The manufacturer goofed up on that one.

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