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Everlast PowerARC 300 Capabilities and Current Measurements

Video About Initial Testing
Video About Design and Internals
Video About Return
Initial Testing
Design and Internals
Return

Video About Initial Testing


Video About Design and Internals


Video About Return


Initial Testing

I performed a bunch of measurements with my 2014 Everlast PowerARC 300, my clamp-on current meter, and my volt meter. I start by reviewing the welder and Everlast's claims, then I perform a variety of tests, and I finish with summaries and conclusions. The maximum sustained arc current I saw was around 260A. I only saw 300A or above while short circuiting. Low current TIG suffered because I could not disable arc force, which consistently added 40-50A to the low end. The minimum TIG current was around 70A unless I was long-arcing. The actual welding current did not usually match the front panel setting. The welder had no problem running 1/16" 6013, 1/8" 6011, 1/8" 8018, 5/32" 7014, 5/32" 8018, and 1/4" 6010 electrodes.

While the welder will work fine for most things I want to do, it doesn't quite seem to perform up to specifications or expectations. It only produces 300A during short-circuit conditions and for very small amounts of time during hot start, so it isn't really capable of the claimed 60% duty cycle at 300A/32V. Don't get me wrong, this welder is over powered for most things I need to do and it will run a 1/4" 6010 electrode at 260A no problem. The adjustable arc force does not seem to have much adjustment, which impacts low-current scratch-start TIG. Here's what I would suggest fixing in future versions:

Here is an example of not quite meeting the specifications. The two meters weren't synchronized, but the same story is true for a few frames on either side of these shots and the measurements immediately before and after these. Here you can see the actual current of 259A is well below the panel setting of 305A. You can also see the arc voltage is 27.25V, which is below the rated 32V. In the other long-arc carbon-arc shot, you can see about the same 250-260A, but at a voltage above the rated 32V. It seems the welder should have enough voltage headroom to produce more welding current, but something in the control circuit limits output to less than the 300A rated output. This seemed to hold true regardless of hot start, arc force, or 6010 port setting.


Here are some summary charts from my initial testing.





Design and Internals

Everlast tech support suggested that my PowerARC 300 might have come from the factory out of calibration. That told me there are adjustments inside the unit. While I was waiting on calibration and adjustment details, I decided to open up my PowerARC 300 to check it out. Overall, it seems pretty clean and well organized inside.

Here's a photo of the control board on top.


Here's a photo of the rectified DC capacitor board on the bottom and the IGBT inverter on top.


Here's a photo of the other side of the capacitor board. You can also see the three phase bridge rectifier attached to the bottom of one of the large heat sinks.


Here's a photo of the fan, toroidal welder transformer, and DC output rectifier diodes.


Here's a photo of the main DC output inductor on the left and the extra 6010 negative port inductors on the right. The two extra inductors for the 6010 port use pretty small (2x 12-14AWG) wire, which seems under sized for 300A. Notice the discolored insulation on the top of the 6010 inductors compared to the bottom where the copper bar acts as a heat sink. I didn't have any problem running 6010 electrodes using the normal negative port in the foreground.


AC power is rectified to DC and smoothed by electrolytic capacitors. The 240*1.414 = 340V DC feeds the IGBT inverter. The inverter is a single phase half-bridge inverter design, which replaces two of the switching components with capacitors compared to a full-bridge four-switching-component inverter design. Each switching device and capacitor in this schematic is actually many in parallel on the real boards. The inverter feeds high-frequency high-voltage AC to the welder transformer primary winding, which is the load in this schematic.


The welder transformer converts high-frequency high-voltage low-current AC to high-frequency low-voltage high-current AC. The welder transformer has a center-tapped secondary winding, which feeds a two-diode full-wave rectifier circuit. The diodes are actually many in parallel on the real board. That converts the high-frequency AC to DC. The DC output is smoothed by an inductor not shown in this schematic.


The IGBTs are
Infineon IKW75N60T devices with K75T60 stamped in the plastic. They are rated at 600V and 75A@100C. There are four IGBTs in parallel for each switch of the half bridge. This is one place where the full-power 60% duty cycle limitation might come from. Each bank only conducts half the time and half the average input current. You can see there are empty slots for two more IGBTs on each side of the inverter. That would allow some flexibility in component selection for a given current capacity or it would allow the same board to be used in a higher current capacity welder.

The DC output comes from two banks of four parallel Fairchild FFA60UP30DN Ultrafast Dual Diodes. The package is marked with F60UP30DN and they are rated at 300V peak and 60A average rectified forward current. Considering that each bank is only conducting half the time and half the average output current, four of these in parallel per bank seems more than sufficient for 300A average DC output. There are three empty slots for more diodes on each side of the rectifier. Again, that allows component flexibility or application flexibility.

Return

I never got any specific adjustment or calibration information from Everlast. They did tell me that the potentiometers are for minimum display current, maximum display current, minimum actual current, maximum actual current, and PWM voltage supply. I couldn't get anything more specific. They did not associate functions with specific potentiometers or provide any sort of adjustment/calibration procedure. Apparently my questions and YouTube posts were making them nervous. They could have easily provided me with the requested information if I agreed to void the warranty. They did not offer to exchange the unit for one that actually produces 300A. Instead, they said they preferred for me to send it back for a refund. I shipped it back and they refunded the purchase to my credit card 10 days after return delivery. On a positive note, the
PowerPlasma 60S seems to perform pretty close to specifications.