I have a Baldor that was left out in the rain for some weeks. Used on a RPC the motor would just hum and not move. Same thing as you describe.
In fact I remember this thing appearing here every few times with no real resolution except that the motor is not 100%.
What about the temperature change. Cab repeated freeze and thaw events make rotor laminations crack or disperse due to water expanding to ice.
If so, would a new motor be better off having a complete sealing job done. Wouldn't have to spray, just brush with no mask.
During the process of taking apart the VFD I saw that the heatsink compound on the hybrid looked like
it was half covered (void spots). Time for a new coat.
I have not studied what happens when black plastic case start caps are immersed in water. Are they vented? I don't use them.
The oval caps can be used as start caps but the largest size I can get is 100 uF. But they are totally sealed.
Something that dissolves rust but doesn't attack aluminum. I have used EdFed from Ace Hardware on steel. Works the best.
I think it brightens aluminum. Soaking for a long time will etch. I have used vinegar too. Even 30% grade vinegar.
I have some Nason-496 clear with 483-78 hardener.
At first...
Corrosion could be forming between the sheets of steel in the rotor. Producing a weak flux region.
Wonder if dipping the whole thing to dissolve rust would fix it. Then clear coating with two-part clear.
The motor connects directly to a VFD. I could cut the signal to the digital input on the VFD. Hopefully the VFD will always respond.
Maybe one of those e-stop buttons that double as a power switch. I mean the one that twists and pops out then push in again.
https://www.oempanels.com/compressor-control-panel-example
All I have is a door with interlock switch. The is a 240 VAC to 120 VAC transformer and the VFD.
The 120 VAC is used outside the VFD enclosure box. It powers a digital pressure switch and some other circuits.
From the small 120 VAC box...
To follow the rule I should be using a 10 Hp vfd. My derate is for periodic on/off. Not continuous. Not something a standards agency would approve.
I though about increasing the size of these four 560 uF caps. The next size up is 680 uF. The next is 750 uF.
I ask if increasing DC bus...
On this forum I have seen posts about pressing shafts out of rotors. Need more than one of those bench presses for that.
Are you thinking about trimming the rotor diameter to fit? What about the location and size of the two bearings? The shaft?
I guess you could make a new shaft.
I would dig...
I have been hum-bugged before. What does your starting circuit look like?
Did you know Phase-a-matic convertors are made with Baldor motors with lightened rotors and no shaft.
Cutting a motor shaft off is something only a heathen would do. I like the shaft but don't like being given one...
Nobody has mentioned that I am not following the rating rule.
7.5 Hp vfd with 5 Hp motor. It works on the edge. Still deciding about a new (correct size) one.
I replaced the DC bus capacitors and now the AB vfd works as good as before. Thanks.
Now if I get an over-current fault I know what to look at. The old capacitors had the same reading (560 uF) and discharged at a slower rate than
brand new replacements. This makes it difficult to determine if...
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