magnetek gpd 503 on single phase

hello all,i am wondering if a magnetek gpd 503 will run on single phase
i have a 3 phase 5hp motor on a screw hoist that i am looking to run
the vfd is advertized as a 30hp.
i have not a lot of knowlege on vfd,s and was hoping the gurus here would have some insight

i was also considering a 15hp rpc.the vfd is less expensive but dont want to waste money on something that
will not work

thanks
brett

The manual mentions nothing about running with single phase input. It might be possible, or it might not.

If it is possible (if there is no phase-loss protection), then you would probably want to use a drive of double the capability in HP or current that the motor actually requires.

You do not want a VFD that is too big in HP capability vs the motor, because then the current limits may not be able to be set accurately for the motor.

GPD503 was capable of accepting single phase input, but needed at least a 50% de-rate. A 30HP drive for a 5HP motor is overkill, but would work, so long as you pay attention to the settings for motor overload protection, parameter Cn-09. It can be adjusted down to as low as 10% of the rating of the VFD, so that would work for you.

Something to keep in mind when buying old drives: that drive is almost 20 years old now, so if it has been sitting on a shelf without being powered for more than a couple of years, just applying power to it now can cause irreversible damage to the capacitors. You will need to perform what's calls a "capacitor reforming procedure" and if you are not electrically savvy, that may be daunting for you.

Also, "hoist" is a concerning subject when applying VFDs. If the hoist has an electrically powered brake, you must separate out the brake circuit from the motor circuit and come up with a way to control the brake outside of the VFD. Getting that wrong can be dangerous. but if by "screw hoist" you mean it has a right angle worm gear drive, they usually don't have or need mechanical brakes.

thanks for the replies.i ended up buying a 15 phasemaster rpc seems to work fine,although on my screw hoist(5hp) with my 4500
pound land rover if i stop in mid height and try to continue it(the hoist) struggles a little.
i find the phase master a little noisy when at idle but quieter under load
i think the heavy load of lifting the land rover is not comparable to starting a 5hp lathe or milling machine
i still may buy the magnetek to see how it is
brett

Jraef said:

Something to keep in mind when buying old drives: that drive is almost 20 years old now, so if it has been sitting on a shelf without being powered for more than a couple of years, just applying power to it now can cause irreversible damage to the capacitors. You will need to perform what's calls a "capacitor reforming procedure" and if you are not electrically savvy, that may be daunting for you.

Click to expand...

The reforming procedure I use isn't desperately difficult, but does require a variable supply of some sort - I use a Variac - and something to limit the current - a proper old-fashioned 100w bulb in series with the line. Ramp up the Variac voltage from zero in small steps (5-10v) over a few hours to full input voltage, keeping an eye on the bulb which will briefly glow on each voltage step but shouldn't light brightly or constantly. Eventually the VFD's fan will kick in, a Good Sign, and the soft-start relay will close (usually audible) when the reservoir capacitors are close to working voltage.

Variacs aren't expensive secondhand and you'd only need e.g. 500w - 1kw rating for the reforming procedure, probably less.

Dave H. (the other one)

Variacs USED TO be cheap, then all of the wannabe guitar heroes found out about using them on the amps to get certain effects and all of a sudden, the prices on used ones skyrocketed, at least from a relative standpoint. I bought one a few years ago for $10 at a flea market, then I gave it to someone that needed one, assuming I could replace it cheap if I needed it again. Now, a POS WWII vintage variac fetches $150-$200 on eBay, even though you can get a new piece of Chinese crap for the same price (corona virus is added for free).

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