Welding Tips and Tricks

In much of what I have read, HF start is listed as causing problems for other electronics, but it's unclear if it is simply an electrical disturbance or if is it more like an EMP event.

I don't have a problem with noisy reception or possibly missing a call on the cell phone in my pocket, but if my car/motorcycle is in the shop, I would hate for HF start to permanently wipe out the electronics on either vehicle.

A silly question perhaps, but I've been visited several times by Murphy lately and would rather not tempt fate.

Regards

Christian

It is not an EMP event and will not affect anything that is not physically connected to the welding circuit.

Some are concerned that the HF start current might pass through and damage an engine management computer if welding on a car. This, I think, is possible but unlikely as a vehicle is a very noisy electrical environment and there are significant protective measures taken to protect electronic components.

A mobile phone or a vehicle in the vicinity are safe from all but sparks.

Jack

High frequency used with TIG and the EMF created by all electric welding can affect items in the vicinity, pacemakers are the common example. Never had issues with vehicles in the area, worked with banks of 400A HF start pulsed TIG machines. Trucks, vans and forklifts all came near with no issue.

Do know the following about HF and cars;
1. HF will affect items in the surrounding area, so you need to be careful.
2. Some modern electronics, including those in cars, are well shielded to stop interference.
3. If you weld on a vehicle then remove the battery for sure, and I wouldn't use HF.

FWE wrote: High frequency used with TIG and the EMF created by all electric welding can affect items in the vicinity, pacemakers are the common example.

That's interesting. I have not heard about any bystanders whose pacemakers were affected by HF start or welding in general. That would make anyone with a pacemaker vulnerable in many places in the community.

Do know the following about HF and cars;
1. HF will affect items in the surrounding area, so you need to be careful.

What specific affect are you referring to?

Thanks, these are things that are good to know.

Jack

Jack Ryan wrote:

FWE wrote: High frequency used with TIG and the EMF created by all electric welding can affect items in the vicinity, pacemakers are the common example.

That's interesting. I have not heard about any bystanders whose pacemakers were affected by HF start or welding in general. That would make anyone with a pacemaker vulnerable in many places in the community.

Do know the following about HF and cars;
1. HF will affect items in the surrounding area, so you need to be careful.

What specific affect are you referring to?

Thanks, these are things that are good to know.

Jack

So have a look here, wee bit from TWI about pacemakers and welding. Never looked further into it, you do make a good point about individuals with pacemakers being potentially vulnerable in many places though.. Other items that can be affected are unshielded electronics, for example old stuff designed for a simple task, say a door opener.

Thanks guys,

I was just unsure as the way manufacturers describe HF start..... they write things so vaguely.

I just wanted to be sure that if I sat down at the welding table and forgot I had my phone in my pocket, I wouldn't be needing to buy a new one! Ditto for my Yamaha. I'd hate to have it screwed up just because I forgot.

I guess I should have known better... I'm a ham and I'm licensed to run 1kw on HF. When you light that kind of transmitter up, there's no need to power your fluorescent tubes... they glow all by themselves! The ends of a wire antenna can develop a corona depending on the frequency and if you touch it, rf burns are the result! It was kinda neat watching mobile antennas with the old brass ball from a toilet being used as a "corona ball" to prevent the end of the antenna from burning.

Thankfully, I don't have a pacemaker or I'd have to look for a different hobby.

Regards

Christian

It is EMP. Just at a relatively low intensity, and series of pulses instead of just one big pulse. Basically, it is electromagnetic radiation which can induce voltage into sensitive electronic components such as ICs if not properly shielded. When such components get voltage added to parts of them unexpectedly while they are operating, they will understandably begin to operate erratically. This is the main concern for HF TIG...sensitive electronics that are in use will become erratic and unreliable, or may just stop working completely while the interference continues. This is obviously a problem if welding near heart monitors in a hospital or nuclear reactor control circuits, etc, etc...

I don't believe that the induced voltage itself from HF TIG is likely to permanently damage any components under normal circumstance...at least I have never heard of such permanent damage. However, it is certainly possible given enough energy. It could cause collateral damage, though. For example, if the logic suddenly latches a relay that was not supposed to be latched at that time, a motor could start spinning and cause damage.

You can see the effects for yourself...Just grab some of the cheapest electronics you have around that use some sort of logic (cheap because they will likely have either poor or no shielding), turn them on and strike an arc near them using HF. You'll see some of them start to behave erratically. A very cheap multimeter is a good choice, or some of the older electronic clocks with digital displays.

FWE wrote: So have a look here, wee bit from TWI about pacemakers and welding.

That is for individuals that are welding and accidentally put themselves, albeit fleetingly, in the circuit or rarely, are so close to an arc to be in a significant near field (centimetres). Not for passers by.

EMP is a very energetic electromagnetic pulse that is radiated, not something that is conducted. There is a huge difference between Pulse TIG or HF start, and EMP.

Even if it is called EMI rather than EMP, nothing bad (electromagnetic) will happen to cars, motorbikes or people that are in the area

Jack

Jack Ryan wrote: EMP is a very energetic electromagnetic pulse that is radiated, not something that is conducted. There is a huge difference between Pulse TIG or HF start, and EMP.

EMP is a very broad term and can originate from many sources and at many levels. It simply means an electromagnetic pulse. There is also the more narrow usage of the term EMP which implies the sudden and highly energetic pulse you mentioned, and is often spoken of in weaponized form. Certainly, this is not applicable to TIG welding as mentioned. But the broader definition is still quite relevant here.

Spartan wrote: EMP is a very broad term and can originate from many sources and at many levels.

We must work in different fields. In my decades of Engineering, it has always had a fairly specific meaning.

Thanks

Jack

But wouldn't there be different levels of EMP's?

IE different radius of affect the EMP would have based off intensity of discharge etc?


Also I've been told by the mechanics at work that whenever welding direct on a vehicle to either fully disconnect the battery or put a surge isolator on the battery to protect the sensors and more importantly the main brain computer of the car.

I've got no real confirmation that my rig welder will fry the computer or alter it and make it not function correctly so I just do what they say and slap the isolator on and I haven't had a car not start after welding yet.


Perhaps I can get a car from 'scrap row' and do some tinkering. Like weld far from the computer with no protection and see if it starts then get closer to the electronics and see the affects.

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Toggatug wrote: But wouldn't there be different levels of EMP's?

IE different radius of affect the EMP would have based off intensity of discharge etc?

Yes, there are small pulses like lightening strikes and large ones like nuclear blasts and some solar activity.

Also I've been told by the mechanics at work that whenever welding direct on a vehicle to either fully disconnect the battery or put a surge isolator on the battery to protect the sensors and more importantly the main brain computer of the car.

That is if you are welding on the vehicle and welding current passes directly through the battery or other electronics. An EMP is induced or, if you like, transmitted like a radio signal.

I've got no real confirmation that my rig welder will fry the computer or alter it and make it not function correctly so I just do what they say and slap the isolator on and I haven't had a car not start after welding yet.

If your car is not in the welding circuit, it will not break.

Jack