joebass1977
New User
- Location
- Western ny
- Occupation
- Welder fabricator machinist
I own a small one man fabrication and machine shop. I have a 10ft 1/4" cincinnati mechanical shear I bought used 11 months ago. It had older electrical mismatched garbage on it with no cover on a some of the boxes. I was running off a cord into a 60 amp 3 phase welder outlet, until about 8 months ago when I finally got around to painting it and upgrading the electrical/wiring. I bought a new surplus 30 amp combination starter on Ebay with a max 7.5hp motor rating on the starter. Ran it on a 40 amp 8 ga wire circuit.
It had a 5hp motor on it that took almost a full minute to get to operating speed.
Fast forward to 2 weeks ago.... I started it up and it was cold in the shop, 35 degrees or so, as I had just gotten there. I noticed it was taking longer than normal to get to speed so I walked over and saw the motor was smoking a little. Turned the switch off and walked away.
After my shop warmed up I tried to run it again and it was seized up. After doing some research it seems most of these shears came with 7.5 hp motor. Last week I found a new Baldor 7.5hp with the same frame size locally at a surplus place still on the shipping skid. Motor hooked up and worked fine to test. I just got around today to putting the pulley, and new belts on and running it. It ran for 5 seconds and tripped the 40 amp breaker. Tried a few more times and same results. Hooked up and my clamp meter and some how it's drawing 130 amps! Took the belt tension off and ran with just the pulley on the shaft and it runs fine pulling 18 amps on start up then drops.
I'm not an electrician but know enough from researching and wiring new to me machines to get most things done, but I'm not understanding this at all. First, I don't know why my overload protection didn't save my 5hp, also why is this running such a high amperage? It never gets to speed before it trips the 40 amp breaker. Also it's not blowing the fuses in the disconnect.
Any thoughts????
I
It had a 5hp motor on it that took almost a full minute to get to operating speed.
Fast forward to 2 weeks ago.... I started it up and it was cold in the shop, 35 degrees or so, as I had just gotten there. I noticed it was taking longer than normal to get to speed so I walked over and saw the motor was smoking a little. Turned the switch off and walked away.
After my shop warmed up I tried to run it again and it was seized up. After doing some research it seems most of these shears came with 7.5 hp motor. Last week I found a new Baldor 7.5hp with the same frame size locally at a surplus place still on the shipping skid. Motor hooked up and worked fine to test. I just got around today to putting the pulley, and new belts on and running it. It ran for 5 seconds and tripped the 40 amp breaker. Tried a few more times and same results. Hooked up and my clamp meter and some how it's drawing 130 amps! Took the belt tension off and ran with just the pulley on the shaft and it runs fine pulling 18 amps on start up then drops.
I'm not an electrician but know enough from researching and wiring new to me machines to get most things done, but I'm not understanding this at all. First, I don't know why my overload protection didn't save my 5hp, also why is this running such a high amperage? It never gets to speed before it trips the 40 amp breaker. Also it's not blowing the fuses in the disconnect.
Any thoughts????
I
