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Author Topic: Century motor start resistor value?
Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 12-04-2006 12:37 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
My Centurys (MSAs with MTR-3-67 soundheads) have neither flywheels nor starting resistors, nor can I afford inverters. They come up to speed quite quickly and I assume that this is not good for the mechanisms.

What is the value of the "standard" resistor that is found in the little box that is normally attached to the motor? Oddly, it is not listed in the R-3 soundhead manual on this site. Does the resistor go across the hot or neutral AC wire? Do I need the flywheels, too? These are my personal machines and will receive only occasional home use. In their previous lives, they were used occasionally in a screening room.

In case it matters, these have the 1725 RPM, 1/4 hp Westinghouse motors of whatever type was shipped with the machines circa 1970.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 12-04-2006 02:58 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Depends on the motor
usually it was around 40ohms and connected in serries with the start winding

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 12-04-2006 06:11 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
You absolutely need the flywheels; otherwise you will absolutely replace the main drive gear often.

The small resistor is wired only into the start winding. Value is unknown, but I think I have some in the shop.

My favorite resistor is wired into the hot wire and is a 150 watt, 2 ohm, adjustable resistor. Hard to find lately. Louis

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