Delta Bandsaw Runs Backwards

[Dann757]

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

 

[waross]

My bad. I didn't focus on the box with the magnetic starter in the picture. I was looking at the push button station.
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
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"Why not the best?"
Jimmy Carter