Inverter vs. Transformer TIG machines

Hi - I am a frequent lurker in this group.

Apart from weight, lower power consumption for the same output (which favour inverter machines) and cost (which favours transformer machines) what are the pros/cons of a high end inverter TIG/stick power source as opposed to a high end transformer TIG/stick power source?

My summary so far is:

Inverter machines have the benefits over transformer machines that they:

- are much lighter than comparable transformer-based machines;

- are more efficient in that they consume less power for the same welding output current;

- they can provide variable frequency on AC TIG which provides better control;

Inverters have the disadvantages over transformer machines that they:

- are often more expensive than transformer machines having similar output capabilities;

- if they break they can be expensive to fix;

- some lower end inverter machines are not able to a good job with all types of rods when stick welding (6010 is a demanding rod that some machines cannot do a good job with);

- it is easier to find a transformer machine if you need high maximum power capabilities are limited - high output transformer machines (over 300 amps max output) seem to be more common than similarly high powered inverters.

- maybe the expensive parts of a transformer machine will have a longer lifespan than the expensive parts of an inverter machine.

- are sometimes designed with 3 phase input power in mind, they can be powered with single phase but the duty cycle can be lower on single phase. The transformer based machines are designed for use on single phase.

If portability is not important does one technology do better than the other in any welding situations?

Do today's higher end inverter machines do as well stick welding as a good transformer machine?

For example, are there any welding situations where a Miller Dynasty 300 would be at a disadvantage to a transformer machine like a Syncrowave 350 or a Lincoln Precision TIG 375 or vice versa? If the group had all of these machines hooked up and ready to go which would you use for TIG / for stick (and why?).

Apparently people who have each of these machines really like them. The manufacturers say that they are FABULOUS. Is it a coin toss?

This only applies to old Powcons.

The only disadvantage the inverters have against comparable amperage transformers is duty cycle. A Syncrowave 350 has a much higher duty cycle. A more appropriate machine to mach a Dynasty 300DX against is a Syncrowave 250DX.

------------------------------------------ Syncrowave 250DX

Input Power

1-Phase Power

Rated Output

200 A at 28 VAC, 60% Duty Cycle

250 A at 30 VAC, 40% Duty Cycle

Output Power Range

5 - 310 Amps

Net Weight * 407 lb (185 kg)

Base price for just the machine Around $2000

-------------------------------------------- Dynasty 300DX

Input Power

3- or 1-Phase Power

Rated Output

DC: 200 A at 28 V, 40% duty cycle

AC: 250 A at 30 V, 40% duty cycle

Output Power Range

5 - 300 Amps

Net Weight

90 lb (41 kg), w/o Aux Power Base price for just the machine Around 00

--------------------------------------------------------------------

If you look at those numbers you will see that the Syncrowave 250DX has the same duty cycle on AC and a slightly higher duty cycle on DC.

It is a matter of how much money you have to spend, and how important the features of the inverter are for you.

To put this in another perspective I am thinking of selling my Maxstar

200DX and buying a new Dynasty 200DX because the warranty has expired on my Maxstar after 3 years. If it blows a board now I am stuck with the full cost of repair.

Inverters that are out of warrantee are a bit of a liability for a business.

A hobbiest who isn't using their machine that hard, and keeps it clean doesn't really have to worry about that, but a business does.