You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
unisaw won't always start
- Thread starter gungatim
- Start date
The mag starter could be faulty, it could be the start switch not making proper contact , thus not pulling in the mag starter . it would have to be diagnosed.
the mag switch is an electro magnet that becomes energized when you push the start button. it pulls in contacts that are rated for the motor load and starts the motor. if there is a power failure, the contacts open . when power resumes it would have to be re started again. there may also be an overload protection in the switch,
a regular light switch is not an alternative
the mag switch is an electro magnet that becomes energized when you push the start button. it pulls in contacts that are rated for the motor load and starts the motor. if there is a power failure, the contacts open . when power resumes it would have to be re started again. there may also be an overload protection in the switch,
a regular light switch is not an alternative
wyliesdiesels
Well-known member
Do you have an air compressor?
Blow out all the dust.
Blow out all the dust.
Check the control station( start /stop buttons) for the saw they used NEMA type one controls & debris may may be impeding making contact, BTW they quit supplying 220 V motors way back when Rockwell still owned them.
If it has mag controls, there will be a number or contacts in series with the starter coil (ie, the STOP button, the Run contacts on the starter, and possibly an overload switch). I would check the continuity of that circuit.
Regarding the lack of 220 motors: How could you run a 3hp motor on less than 220 volts? My '69 Unisaw has 3hp (single phase), and it requires 220 volts.
The old 3 phase were 220/440V and RI repulsion start, induction run single phase motors were 110/220V which ceased being avail. in the 60's are the only OEM motors that were offered with those voltages on Unisaws, the motors offered for those saws are 115/230, 230, 230/460, & 200-208V mixed in. 220 is obsolete and has been since before WW II.
The old 3 phase were 220/440V and RI repulsion start, induction run single phase motors were 110/220V which ceased being avail. in the 60's are the only OEM motors that were offered with those voltages on Unisaws, the motors offered for those saws are 115/230, 230, 230/460, & 200-208V mixed in. 220 is obsolete and has been since before WW II.
Now I see what your saying---you are talking about the actual line voltage of 220. I tend to think that everyone here uses 220/230/240 interchangeably, and meaning both sides of the fuse panel (not just one). And 220 volt motors will run fine on contemporary 240 volts. But yes, true 220 line voltage went away years ago.
wyliesdiesels
Well-known member
Now I see what your saying---you are talking about the actual line voltage of 220. I tend to think that everyone here uses 220/230/240 interchangeably, and meaning both sides of the fuse panel (not just one). And 220 volt motors will run fine on contemporary 240 volts. But yes, true 220 line voltage went away years ago.
This group has members from all over the world. While the US uses 240v, many other countries use 230v and 220v. Seeing as how many members dont put their location in their profile nor put their location in their OP, it is never good to think or assume someone is using 220v interchangeably with 240v....
pattenp
Well-known member
I believe it's the magnetic starter. The momentary switch you are pushing you can check that first with a meter to see if it's getting good contact across the terminals as you hold down the button. Obviously with the power disconnected. That switch just closes as you push the button and opens when released. It sounds like the mag starter is not staying locked on because as you released the start button it cuts out.
This group has members from all over the world. While the US uses 240v, many other countries use 230v and 220v. Seeing as how many members dont put their location in their profile nor put their location in their OP, it is never good to think or assume someone is using 220v interchangeably with 240v....
I still don't get it. Unless you are referring to 3phase vs single phase, I don't see the big deal in 220/230/240. What is the issue in lumping SINGLE phase 220/230/240 all together?
The starter is a Delta LVC, Low Voltage Control, get a multimeter & start by checking the control transformer for 24V output, if the problem was not intermittent then would say press the reset button on the overload relay in the LVC enclosure, more later.
wyliesdiesels
Well-known member
Could also be an issue with the latching contact.
wyliesdiesels
Well-known member
That would make sense.
Stop buttons are wired in series with start switches.
EDIT: Just watched the video. I see its a combination switch. Just replace the whole thing.
Stop buttons are wired in series with start switches.
EDIT: Just watched the video. I see its a combination switch. Just replace the whole thing.
Last edited: