Steve

Most of the time I use digital meters because of their accuracy. The meter I used for the tests was a digital line clamp. It is far more accurate than my old Amprobe.

After I turned three sheets of green in color, I have immediately decided to convert to a start-winding ballast as soon as I possibly can. In event of a lock-up, it'll probably take the breaker out faster, hopefully. I think the ballast will still protect the start windings from burning out, especially with projector No. 3. Just a guess, but I think the resistor in No. 3 is rated at about 50 watts"

Probably the resitor save the machine from other gear damage when it locked up

THe resistor should be mounted in a ventelaited metal cabinet and heagt resistant wire is normally used (appliance)
The wattage should be 200 watts in most applications not 50

The Gould (Century) motor that I did testing on probably is a 50 Ohm power resistor which has been in service for at least 20 years now. If it is a 2 Ohm resistor, there is just no way it could be a 200-Watt device It is just too physically small. The Gould motor that is on the other machine (by the looks of the ratings) is a very efficient motor as compared to the others I tested. That 50-Watt (if that is what it is) resistor is in the start winding circuit only.

If the use of the 200 Watt resistor desired to be placed in series with the motor, mount it as Gordon suggests to be on the safe side. Don't use any power rating smaller than 200 Watts for this purpose as Gordon already pointed out. I certainly agree with Gordon about that.

As for me, I won't use them in series with the motor. I am converting mine to the way they did it 70 years ago.

Next time I get a chance, I'll verify the rating on that specific resistor used in the Gould motor. I will also verify the size if the resistor in the R&M motor used with the on the 1040 and 1050 soundheads. I am guessing R&M used about a 100-Watt resistor used with the start winding. I would also guess that the power rating and electrical reisitance value of the resistor selected by the motor manufacturer was based on operating characteristics and efficiency of the motor.

Whatever the values are, I'll let you all know as soon as I find out. I might also point out that the less efficient motor may require a 2-Ohm resistor greater than 200 watts, depending on how big of a power hog the motor is.

If the motor is really a big power hog, maybe a 1 Ohm 200-Watt power resistor might be a better answer. There are several variables to take into consideration when the correct size is selected. The "One Fits All" theory may not always be the best solution.

Dick, that is a very good call. Too many people "bump" the motors to verify the projector threading. As you, Gordon and I know, that is a very bad practice and is nothing short of abusing the machinery.

Brad, if you have people doing that to your machines, throw them out of your booth! I would if it were mine...

Looking at the RCA 1040 setup, the R&M motor on the 1040 soundheads use a 40-Ohm starting resistor. The resistor is rated at 70 Watts. Mine is tapped at 26 Ohms. See page 17 of the 1040 manual from the FT Archives.

Below is a picture from the manual. Pardon the quality, as I took a picture of my monitor screen.

Below is a picture from the Oak Harbor booth. The left picture shows the location of the power resistor in the ORC Console. The picture on the right is apparently a factory aftermarket slow start kit.

The advice that Gordon, Dick, and Brad has made is right on target. If those big "dogbones" are installed, mount those things where it cannot set something else on fire.

Steve

Steve, thanks for the info. Those kits work very well! There is absolutely no signs of overheating or deterioration. Since it is using a 25-Ohm resistor and the R&M uses one at 26 Ohms, the 25-Ohm is what I will experiment with. Since the Dayton motor is so much of a power hog, I will stay in the vicinity of a 70 to 100-Watt rating and get rid of those big 200-Watt dinosaurs. If I have to mount it in the console, I will put a heat shield in it to keep any heat away from the wiring in event of a starter switch failure.