Welder Wiring Safety

[ASKANDY]

Good point cope.

Most of the machines that are of the 200/230 variety have the plug installed and matching the receptacle is easy. The units where multi voltage inputs require us to not put a plug on seems to be where a bunch of confusion sets in. When the owner has to pick both plug and receptacle, this is usually where the guy at the home improvement store gives the poor man a dryer plug and receptacle.

I think it was a cost thing where we stopped including the receptacle with the T-bolts.

a-

[PJB]

Heiti,

thanks for all the great info.

After reading your post it made me wonder if my wiring was correct, so I broke out my manual and I'm confused a little bit. The manual gives recommended circuit breaker ratings without power factor correction and with power factor correction. Which one do you go by? What is power factor correction?
My welder is a syncrowave 250 and the wiring was done by an electrician he used a 100 amp breaker with #4 wire, is this correct?

Thanks for your time


Paul

[JWELD]

I am fortunate to have a separate meter/service entrance for my 800 sq ft shop. It really does not cost much. I get a separate bill each month from the utility company. Most importantly, I don't have to worry about overloading the service. In addition to a full line of Miller's, I also have a complete machine shop with a heavy duty threephase rotary convertor.

Just a few word for thought

[H80N]

Paul
according to the pdf of your manual (pg 21 have included link) they reccomend #6 wire and a max of 110amp breaker... what this means is that you have heavier wire than the minimum which will not hurt and a marginally smaller breaker.. that may trip if you are running your machine WIDE OPEN...but will be fine for normal use... all in all have if erred at all you have erred on the side of safety... sounds fine.... now as to power factor correction... is a little complicated to explain.. but is many times accomplished with some capacitors on the input side of the machine to help compensate for the phase shift that the inductive load of your welders transformer presents to the line.... if all of that sounds like gobbldygook... your meter will register fewer watts with the compensation... is more complicated than that.. will try to find a site that gives a better explanation... and will post if I can

http://www.millerwelds.com/om/o353u_mil.pdf

hope this helps
Heiti

[H80N]

Power Factor Correction

Paul
here is a site that explains Power Factor Correction much better and in more depth than I have....
.
http://www.lmphotonics.com/pwrfact.htm

And JWELD you may find this useful for your machine tools as well.. because it will take some of the load off of your three phase converter if the motors are not corrected already...

As a general note.. this site deals with electric motors.. but transformer type welders are also the same type of inductive load so the same rules apply..

(EDIT AND ADDITION)

right after I posted the first site... occured to me that the first site may bury some of you in engineeringese.... here is a site that explains it in english... sorry...

http://www.seav.vic.gov.au/ftp/advic...orrect_1_0.pdf

hope this helps
Heiti

[ASKANDY]

Paul,

I would assume your welder is not a power pactor corrected unit. Unless you specified at the time of your order you wanted power factor, your machine would come as a standard unit. As Heiti said, this is done with a bank of AC capacitors to compensate for the Volt/Amp phase shift. The goal is to get the Voltage to track in sync with the Amperage. In any event, I would say your wiring is fine.

Andy

[H80N]

Power Factor Correction & Inverters

What about Inverter Welders??
... Inverter welders are a totally different critter than transformer welders as far as type of line load is concerned...
whereas the transformer represents what is called a sinusoidal load, in that it uses the entire 60cycle wave as it comes down the wire.... Inverters on the other hand use parts of that waveform depending on the load... and thus are called non-sinusoidal... to put it simply... part of the front end of an inverter welder has a chopper circuit in it.. and that chops up the incoming wave..essentially turning the power on and off very fast according to the amperage requirement at the time...
the transformer machine can use what is called passive correction which is usually capacitors... the inverter machine needs an active power factor device... a smart box that takes into account that switching and applies the correction accordingly....
The good news is that it appears that the Miller Engineers have incorporated this correction into the design of the current inverter line... it sure looks like it from the efficiency numbers that I am seeing on them...
probably could have just said that they are so efficient that you should not worry... for anybody that wants to study this in more depth here is yet another link.. for the rest I dont blame you..

http://www.coolpowersolutions.fi/Lib...r_Factor_C.pdf

and I think that we have coverd this subject
thanks guys
Heiti

(edited for clarity)

[ASKANDY]

inverter theory

Actually, our inverters work differently than you decribed. Ours do not use just a portion of the sinusoidal input. It uses the entire input and actally appears to be more of a capacitance load than an inductive one. Our power factor correction in the inverters is achieved with a small inductor or in some cases with the small inverters, nothing at all.
Miller inverters follow this input scenario.

Input Ac to full rectification and filtering by high voltage DC caps.
This is refered to as the DC buss. DC buss is chopped by IGBTs to high voltage, high frequency pulsed DC. This high V, high freq DC pulse appears to be AC when applied to a transformer. (a transformer only requires a change in current to operate) After tranformer, it becomes low voltage high freq which is applied to special high speed diodes for rectification then to a small stabilizer coil and on to weld America.
By doing our inverters this way, you can see that the input AC draw remains stabile and the need for variable powerfactor correction eliminated.

This gave us much better efficiency with less fuss.

Hope this helps

A-

[H80N]

Andy
guess I oversimplified and left out the rectifier.. should have put it in and explained chopped DC ... in new designs Insulated Gate Bipolar (Field Effect) Transistors do the switching.... sorry that I oversimplified.. just wanted to get the Idea across without boring the troops to tears... but yes we are talking apples to apples... the links , have the info that I left out for the sake of brevity...
my apologies
Heiti

[ASKANDY]

Heiti,

Our Inverters have used the I.G.B.T.s for ever. We only used the MOSFETs (which is also a high speed transistor) in the smaller inverters like the older Maxstars.

We always like to think of ourselves on the edge of new technology and with some of the new inverter engines we have coming, you will see even more performance, power efficiency and univoltage input.

Cool eh?


A-

[H80N]

Andy
VERY COOL!!!! when do we see the new ones???
thanks
Heiti

[ASKANDY]

The Dynasty 200 is the first step. It has a univolt input and can run on anything from 110-500V. Other inverters have an internal linking system like the XMT or Dynasty 300s. Those units measure the primary and link between say 230 or 460 and do not have the range in between that the new inverters will have. In other words. Some of the technology is here now.

A-

[PJB]

Thanks guys,

I'm going to check out those sites tonight.
with the 110 amp breaker do I need a 110 amp plug? Do they even make a 110 plug or is a 100 amp ok?


Thank again

Paul

[ncdrakes]

now you've got me thinking

I recently purchased a dynasty 200dx and am in the process of having it wired in. I have a 30A breaker on 230; with a #6 wire running from my panel 5 feet to a 30A receptacle. The receptacle and plug were purchased at Home Depot; both are rated for 30A on 230. Is this plug/receptacle going to be sufficient for this machine? Are there plugs/receptacles specifically designed for welders? This is definately something that I'm not that familiar with. Thanks for your feedback.

[H80N]

PJB & Ncdrakes

pjb.... gotta have more info on machine etc.... what does your manual say????

Ncdrakes
pg 13 of the pdf for your manual says that it draws 27amps 230 single phase.... so it looks like you are fine... here is the link...

http://www.millerwelds.com/om/o2240f_mil.pdf


Guys.... ya gotta read your manuals..... I am just a poor old welder from pennsylvania... helping as I can... but please read the books that come with them... the Dynasty book is 90 pages but looks well worth the read...
hope this helps
Heiti