benha
New User
- Location
- Felton, CA
- Occupation
- Software
Hi,
I'm working on adding a new tool to my home shop and running into an electrical issue I'm hoping to get some help with. Finding "qualified electricians" who know much about industrial electrical isn't all that easy...
The tool is a big, two-head wide belt sander. My shop's power is 1ø 230V, and my 3ø tools are fed by a pair of connected RPCs that provide up to around 100A of 3ø power, distributed through a load center. The sander - bought at auction - was misrepresented as a 230V machine. Actually runs on 460V. So I've installed a reverse-fed 45kVA 460-230 3ø transformer to step the power up for it. It took some doing, but I've got this is all working.
There are numerous motors on the machine and they all work, except for the largest of the sanding motors. This is a 30HP unit. When I hit the (DOL) start button the contactor "stutters". I assume what's happening here is that the inrush current is dropping the voltage sufficiently that the coil in the contactor releases and the circuit opens, which then bumps the voltage back up allowing the contactor to close, ad nauseum until I release the button. (Which I do quite quickly.)
There's plenty of amperage to run the tool at sanding load as long as I don't push it really hard, but I need to figure a way to get that big motor spinning. I'd really like to avoid buying a soft starter like that since it's both expensive and requires a bunch of rewiring.
Anyone have suggestions on more conventional ways around this? Interestingly the motor does start spinning a bit, so I feel like I'm getting "close". Is there maybe a way to add capacitors to the control wiring or something to keep the voltage up enough that the contactor stays closed a little longer?
Anyway, would love any suggestions on how to get past this!
Thanks,
-Ben
I'm working on adding a new tool to my home shop and running into an electrical issue I'm hoping to get some help with. Finding "qualified electricians" who know much about industrial electrical isn't all that easy...
The tool is a big, two-head wide belt sander. My shop's power is 1ø 230V, and my 3ø tools are fed by a pair of connected RPCs that provide up to around 100A of 3ø power, distributed through a load center. The sander - bought at auction - was misrepresented as a 230V machine. Actually runs on 460V. So I've installed a reverse-fed 45kVA 460-230 3ø transformer to step the power up for it. It took some doing, but I've got this is all working.
There are numerous motors on the machine and they all work, except for the largest of the sanding motors. This is a 30HP unit. When I hit the (DOL) start button the contactor "stutters". I assume what's happening here is that the inrush current is dropping the voltage sufficiently that the coil in the contactor releases and the circuit opens, which then bumps the voltage back up allowing the contactor to close, ad nauseum until I release the button. (Which I do quite quickly.)
There's plenty of amperage to run the tool at sanding load as long as I don't push it really hard, but I need to figure a way to get that big motor spinning. I'd really like to avoid buying a soft starter like that since it's both expensive and requires a bunch of rewiring.
Anyone have suggestions on more conventional ways around this? Interestingly the motor does start spinning a bit, so I feel like I'm getting "close". Is there maybe a way to add capacitors to the control wiring or something to keep the voltage up enough that the contactor stays closed a little longer?
Anyway, would love any suggestions on how to get past this!
Thanks,
-Ben
