30% duty cycle, but much higher output) than rated, and it's just fine doing that.

A commercial welding outfit might only run it two shifts a day, and they may not run it at full rated (100% duty cycle) output, but they'll occasionally have a situation where they run it substantially ABOVE that figure (like. In comparison, a Miller industrial welding supply is intended to be wired in, powered up, set up, and put into operation, where it'll run basically continuous-duty, 24/7, for it's entire lifespan. As a result, they're not built to be used in under highly demanding constraints.

Welders sold through SNAP-ON, NAPA, SEARS, HARBOR FREIGHT, etc., are all that way- the manufacturers have no intention on making a name for themselves, and have no interest in competing for industrial customer base. Past that, there are MANY, MANY companies that have welders manufactured and branded with their company name, and there's companies who build welders SPECIFICALLY for having them house-branded and sold. The 'Big Three' are the competetors fighting for dominance in the industrial and commercial welding market, and therefore, they set a very high standard for performance, reliability, and servicability. To cause the motor to run continuously, the transistor which is in series with it will be short-circuit from emitter to collector, or incorrectly constantly turned on by a signal on the base.It's not that they're looked down upon for no reason. You would need to trace the motor wiring to confirm this. This second component will get switched on when the motor is not under power, to short it and bring it to a rapid halt, preventing run-on of the MIG wire spool. It is possible that one transistor is in series with the motor to control the speed, and the other is across the motor terminals ( i.e. Either of these two devices could easily run a typical wirefeed motor, at 24 or 48 volts and 2 or 3 Amps. The MJ15015 specs are: 120 volts, 15 Amps, and 180 Watts. The MJ900 is rated at 80 volts, 8 Amps, and 90 Watts. The normal digital meter test procedure may not show the typical results on a Darlington Pair. That is a pair of transistors in one case, with the amplified current of one feeding into the base of the other, so they switch easily and quickly. The MJ900 is the equivalent of the NTE244, and it is a PNP Darlington Pair. The two power transistors that you found in your welder explain why I discovered data about two alternative components - there are in fact two different ones used in the machine.

Ya212a snap on welder parts