SERVO CONTACTOR, Comes in 2 Versions.
The original 90-Volt type Contactor was found in all Model 2 Servo Systems. Strippit #22591-000. Depending on the Vintage (year made) of the Servo System, there was a external Back-EMF Diode across the coil, and a 2nd Diode that fed the voltage input to the coil. Early Versions did not have the 2nd Diode. There was also a external switch used to pull-in the next contactor in the Servo System,
in a Daisy-Chain way.
This 90-Volt Contactor was also used in Early Model 3
(Not 3A) 150 volt Servo Systems with a External
Voltage-Dropping Resistor, so that it could withstand the higher system voltage.
Model 3A Servo Systems used a Special high-voltage contactor for that improved 150 volt system only.
They had the 2 Diodes Molded-Inside the Coil, and did Not have the external resistor, and did Not (usually) have or
use the external switch. Strippit #22803-000.
These 2 Types of Contactors are Not Interchangeable!
There is 1 Contactor on Each Servo Drive Axis, so typical Strippit Machine would have 3, 1 for X, Y, and T Axis.
Contactors sometimes Overheat and Burn-Out their Coils,
especially in Hot Shops in the Hot Summer.
With Coil Burned-Out, Contactor will No-Longer Close.
As Control does Not know Contactor is Open, there will be
No Error Message at Machine & Control Turn-On.
As there is No Power going to the Servo Motors, you can grab X & Y Ballscrews and Turn them by Hand, which Verify's No Servo Power to Motors. And you get "Excess Error" when you try to Move-Axis as Servo Motors have
No-Power and so can Not Move Axis.
A Good 90 Volt Contactor Coil Measures about 300 Ohms,
a Burned Out "Open" Coil will Measure Millions to Infinite Ohms. We Stock Replacement Contactors!