110v spot welder work on 50Hz?

First, they have 240 Volts and often a little higher.

Second, for 50 Hz you need to derate by 20% so if the welder will take

120 V / 60 cycles you need to run it on 100 V / 50 Hz otherwise you will smoke the transformer. Been there, done that. Now if the duty cycle on the welder is very low you might get away with 120 V OK.

So it comes down to availability of a step down and $$$$. See if you can order a 50 cycle transformer with taps at 100/110/120.

HIH.

Pondering selling my Dayton hand held spot welder vs taking to Australia. Assuming I have a transformer to knock 220 down to 110 that will handle the current, will 50Hz adversely affect performance? Is there anything about that which would require uprating a transformer a bit?

Thanks,

Jon

Sorry, I mean to write: Jon it oughta be OK. The spots will just be 5/6th of normal size.

Thanks,

Jon

"Robert Swinney" wrote: Sorry, I mean to write: Jon it oughta be OK. The spots will just be 5/6th of normal size. ^^^^^^^^^^^^^^^^^^^ No, I think you need to consider the *area,* not the diameter. The spots will be 25/36 the normal size.

Thanks, seemed to me it should work, but my knowledge of electrical and electronics is well within the 'dangerous' range...

Jon

Robert wrote: Jon it oughta be OK. The spots will just be 5/6th of normal size. Jon wrote: Thanks, seemed to me it should work, but my knowledge of electrical

^^^^^^^^^^^^^^^^^^^ Leo writes: Jon, I'm pretty sure he was kidding. But, if you intend to take him sriously, then see my post regarding diameter vs. area.

I wasn't sure, but really, I think spot size has more to do with the diameter of the tips and to a lesser extent, length of weld time. I just wanted to make sure the welder wouldn't go up in smoke if I tried to weld something...

Thanks,

Jon

It probably won't go up in smoke right out of the chute, but I'd keep an eye on it (or, more accurately, a hand) and if it feels like it's getting too hot, then cut your duty cycle down to 5/6 of what you did at 60 Hz.

60 Hz transformers draw more idling current at 50 Hz, and have less amp-hour capacity than at 60.

Have Fun! Rich

"idling current"? The spot welders that I'm familiar with only energize the primary when actually welding. I.e., there is no idling current.

Bob

On Wed, 15 Jul 2009 10:18:23 -0800, the infamous Jon Anderson scrawled the following:

Nope, it won't work.

P.S: Save it for me when I come down next week, eh?

-- Mistrust the man who finds everything good, the man who finds everything evil, and still more the man who is indifferent to everything. -- Johann K. Lavater

Please Explain why it won't work.

-- John G.

On Thu, 16 Jul 2009 19:55:17 +1000, the infamous "John G." scrawled the following:

You snipped the reason from my tongue-in-cheek reply. I wanted him to give it to _me_.

-- Mistrust the man who finds everything good, the man who finds everything evil, and still more the man who is indifferent to everything. -- Johann K. Lavater

It may not work. Transformers are designed with a ET value. That is the input voltage times the time is what determines the max flux density. With 50 hz the time of one half cycle is more than the time of a 60 hz half cycle. So a transformer used at the same input voltage will reach a higher flux density on 50 hz power than on 60 hz power. And depending on the design it may start to saturate the core.

=20 Dan

I think we should plug in a few numbers. The operating frequency changes from 60 hz to 50Hz but not the supply voltage The transformer ratio and hence the open circuit output voltage is unchanged.

The copper loss is almost unchanged unless the iron circuit aproaches saturation.

If the transformer is conservatively designed the working flux density will still be well below saturation flux density. Iron losses are non-linear but increase by very roughly as the inverse square of the frequency change i.e. 60/50 squared about 1.4x Typically the iron losses are about half the total transformer losses so this is equivalent to about 20% increase in temperature rise or, for intermittent use, 20% decrease in duty cycle.

If it's light weight low cost design running as close to saturation as they dare then there will be a larger increase in iron loss. The welder will still work but you may have to severely limit the duty cycle to keep the temperature rise within limits.

Summing up, your welder should work fine on 50Hz. It is delivering the same output voltage so the spot size will be unchanged. The transformer will run hotter so you should be conservative with your duty cycle.

If you are in any doubt about the 50 Hz temperature rise, you can play safe by reducing the supply voltage. 5/6 approx 100V would restore the 60Hz flux density but this gives a 20% drop in output voltage.

Heat output is proportional to V squared so this is equivalent to a 44% downsizing of the welder capability with proportionate effects on spot area and permissible sheet thickness.

Jim

If the transformer takes 110 at 60 Hz, it's safe up to 50/60*110V at 50 Hz (i.e. 92 VAC). There's also a timer in some spotwelders, and that might time differently with 50 Hz. Look at the manual that came with the spot welder, there might be instructions for connecting different taps on the transformer...

A handheld spot welder's on-cycle is very short, often in mS for thin materials, and only about 1.5S for 1/8" total thickness. The thickness limit of most 120V units that I've looked at was about 1/8" total.

The xfmr primary current demand is fairly high (maybe 30A at 120VAC), but also relatively brief in duration.

If you happen to locate a good deal on 240VAC spot welder in the meantime, buy it and sell the 110/120V version. If the Dayton unit is labeled with 110V as the input voltage, it's probably a fairly old unit or I'm guessing that it was manufactured in Japan/Asia or the Mediterranean regions to be labeled with 110V.

The issue of destroying the xfmr because of the 50Hz line frequency is probably of no significance, and a spot welder of decent quality will very likely have a thermal protection device (self-resetting) inside the xfmr, to prevent the xfmr from damage due to overheating.

Thank you for the in depth answer! I am looking to take as much tools and such as possible. It's possible I'd have the only spot welder for quite some distance, so it's worth taking if it'll work. If it doesn't work, it'd be worthless there, and cost more to ship back than it's worth... Sounds like it's worth taking. It seldom gets used, and only light duty cycles, should be ok.

Jon

That is a commonly understood joke among regulars here. Someone wants to know the value of something of obvious value, and someone almost always pipes up and says it's not worth anything but they're willing to pick it up at no charge. There are several variations.

Jon

Where in Oz are you moving to ? I am in the best part, the West, unlike poor Andrew who is a resident of Mexico.

I have an ancient hand held spot welder which I usually use to join galvanised stud, very few of my welds have come apart except when clobbered with a cold chisel.

It is probably worth bringing even though you will need a step down transformer. This will give you an idea of prices here

Alan VK6YAB