Miller Thermal Plasma spray system

[Vijay Deshpande]

Dear All,
I am in the process of re commissioning one old Miller Thermal Plasmatron Plasma spray system. The Plasma gun starts with Argon and go up to 700 amps. How ever once Hydrogen Flow is started to increase Arc Voltage, The machine trips.
What could be reason?
Vijay Deshpande

[loriolo]

Hi Vijay
Some things, the first is what about electric power supply, is it stable or has some noises, like harmonic, the second, which torch do you use, if you start Hydrogen flow at about 700 amps, this like a little wrong, because Hydrogen flow will be started at about 250/300 amp, and very slowly you must increase the H2, while increase the amps (ever slowly), if not your plasma could not reach the perfect stability, and you can destroy the torch components.

[Johnny_Blaze]

Dear All,
I am in the process of re commissioning one old Miller Thermal Plasmatron Plasma spray system. The Plasma gun starts with Argon and go up to 700 amps. How ever once Hydrogen Flow is started to increase Arc Voltage, The machine trips.
What could be reason?
Vijay Deshpande

The power supply tripping is a safety feature, you are exceeding the maximum voltage limitations of the power supply.

As suggested above...introduce your H2 slowly below 300A and adjust to the desired power settings.

700A is a little high...any reason in particular you are using a high amperage with H2 as the secondary gas?

Regards,
John