Delta Bandsaw Runs Backwards
Delta Bandsaw Runs Backwards
(OP)
Thanks if anybody can help. I've seen similar threads. I got this old Delta/Rockwell bandsaw at a garage sale. SER. # BZ2574. I got the guy to plug it in, and I saw it run for a few seconds, but may not have noticed it runs backwards. Motor specs are MASTER
THE MASTER ELECTRIC MOTOR CO. DAYTON, OHIO
SER EX 22238 STYLE 290241 TYPE CS FRAME F56 HP 1/4 VOLTS 115 CYCLES 60 AMPS 4.8 PHASE 1 RPM 1725
I had the motor apart to clean and check. It has a centrifugal mechanism. Capacitor is a Mallory 161 MFD. Cap checks good.
It was soldered in as the 110 leads were. The AC line comes in, and goes to two winding leads. These leads are soldered to a yellow wire that goes to the cap, and a yellow wire that goes to the windings. Motor seems original.
Motor should spin CCW, but it spins CW and the blade goes backwards.
I wound a string around the shaft, and spun it CCW as I hit the start switch. This causes the motor to spin CCW!
Not sure how to proceed. I can provide more details if anyone is interested.
thanks,
Dan
THE MASTER ELECTRIC MOTOR CO. DAYTON, OHIO
SER EX 22238 STYLE 290241 TYPE CS FRAME F56 HP 1/4 VOLTS 115 CYCLES 60 AMPS 4.8 PHASE 1 RPM 1725
I had the motor apart to clean and check. It has a centrifugal mechanism. Capacitor is a Mallory 161 MFD. Cap checks good.
It was soldered in as the 110 leads were. The AC line comes in, and goes to two winding leads. These leads are soldered to a yellow wire that goes to the cap, and a yellow wire that goes to the windings. Motor seems original.
Motor should spin CCW, but it spins CW and the blade goes backwards.
I wound a string around the shaft, and spun it CCW as I hit the start switch. This causes the motor to spin CCW!
Not sure how to proceed. I can provide more details if anyone is interested.
thanks,
Dan





RE: Delta Bandsaw Runs Backwards
RE: Delta Bandsaw Runs Backwards
RE: Delta Bandsaw Runs Backwards
Thanks for the response.
RE: Delta Bandsaw Runs Backwards
RE: Delta Bandsaw Runs Backwards
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: Delta Bandsaw Runs Backwards
If it's from 1958, then that's gotten a good life out of it.
RE: Delta Bandsaw Runs Backwards
The AC coming in should be connected directly to the run winding.
The Ac should connect to one end of the start winding and the other end of the start winding should go to the cap and then to the switch and thence to the other Ac line.
the start winding may connect to the switch, from the switch to the cap and thence to the other Ac ine.
Either way, it doesn't matter.
Interchange the two run winding leads. If the start winding is serviceable the motor should run the other way.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Delta Bandsaw Runs Backwards
Maybe as a test, but nothing else.
RE: Delta Bandsaw Runs Backwards
Have you checked the capacitor or replaced it with a known good capacitor?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Delta Bandsaw Runs Backwards
I switched the yellow leads, with some difficulty, had to get out my serious stained glass soldering iron.
The motor spins counter clockwise now!
The cap had tested good. I hadn't noticed any burnt smell whatsoever, and the black tar looking substance on the windings actually had a drip that stuck out horizontally, a clue that the motor would have been vertical when that happened- so perhaps it is a factory coating.
Grateful that I can keep the original motor on the band saw!
RE: Delta Bandsaw Runs Backwards
If the centrifugal switch is fried together, it will not start, it will sit and hum, burn out the start windings.
If the capacitor is bad, it will not start unless it is pushed.
It looks like the start windings are cooked.
RE: Delta Bandsaw Runs Backwards
The action of the centrifugal switch can be heard as the motor is operated.
Capacitor checked good.
The machine starts and operated with plenty of power to zip through a Douglas Fir 2x4.
This was an impulse buy at a garage sale. It will see occasional use. I do still wonder why it ran backwards in the first place, and there is the possibility that black substance is cooked varnish. No shorts to ground though, and as I mentioned, there is no burnt odor at all.
Perhaps a student got into the motor to re grease the bearings and resoldered the wires incorrectly - Everything was soldered, and there is no distinction between the yellow wires.
I have other motors, just wanted to keep this original.
Replies much appreciated!
RE: Delta Bandsaw Runs Backwards
You may want to verify that before trusting it. That package looks small for a magnetic contactor.
There are some manual starters with a shunt trip for undervoltage release. They are not common. You lucked out if you have one.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Delta Bandsaw Runs Backwards
RE: Delta Bandsaw Runs Backwards
Most of the small manual starters are toggle operated. The push button operator in that small size is unusual and probably no longer availale.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Delta Bandsaw Runs Backwards
Yeah, we have functionally similar devices over here but they're a relatively new style of device. Something like http://www.schneider-electric.co.uk/en/product-ima....
There are older types which are probably closer to what you are thinking of:
Outside http://www.cnczone.com/forums/attachment.php?attac...
Inside http://www.cnczone.com/forums/attachment.php?attac...
Sorry about the links, the [img] function wasn't working.
RE: Delta Bandsaw Runs Backwards
Thanks for the help once again, the level of knowledge here is astounding to me!
RE: Delta Bandsaw Runs Backwards
RE: Delta Bandsaw Runs Backwards
"Thanks for the help once again, the level of knowledge here is astounding to me!"
Most of us have been doing this stuff for a living for a long time, some longer than others.
RE: Delta Bandsaw Runs Backwards
We have single phase motor starters that are about that size. Almost all were toggles but at one time there was a push button version.
As to the wiring of the overloads in the magnetic starter; That meets all past and present codes.
There are two main issues when all three overloads are not used.
The first issue is differential protection. You must pass the current through all three overload heaters in order for the differential protection to function properly.
That old starter does not have differential protection, it is a melting alloy type and each pole functions independently.
The second issue is total heat in the enclosure.
Those starters had a chart pasted inside the case that gave you the correct heater part number based on the motor FLA. As you can see, there is a factory installed jumper in the center pole and the chart will take into account that the total heat in the enclosure is from one instead of two or three overload heaters.
Those melting alloy heaters ran pretty hot and the total heat in the enclosure would affect the tripping point.
To compensate for this, some manufacturers used a slightly different chart for;
-Single phase use with one overload heater used.
-Three phase use with three overload heaters used.
-A basic box as is use on the band saw.
-A combination motor starter.
-Some may use another chart for use in an MCC.
-Another chart may be used if the starter was to be a component in a relatively large control panel.
A note to the OP.
If the starter trips on overload, give it time to cool down and for the melting alloy to solidify.
The melting alloy overloads were reliable and dependable, BUT.
When a production machine tripped on overload, some operators had a habit of pumping the reset button to try to get going as soon as possible. The alloy would often catch and hold before it was properly solidified. Sort of a cold solder joint effect.
Then the overload would start tripping at less than rated current.
Bill
--------------------
"Why not the best?"
Jimmy Carter