SM-6495 - Ansaldo STS

General Maintenance and TroubleshootingIf necessary, the air gap may be adjusted as low as 0.015” and as high as 0.025” to obtain the properpick-up and drop-away values.3.2.6. GearmotorThe gearmotor (see Figure 5-1, Figure 5-3, or Figure 5-7, Item 40) is a contained unit with a special gellubricant sealed in the gearbox. Should the gearmotor become faulty, it is recommended that the entireunit be replaced. The hold clear device is attached to the gearmotor at the bottom of the gatemechanism.1. Disconnect (white) brake wires from contacts labeled 1B and 4B on 12-volt systems and 2B and4B on 24-volt systems.WARNINGTo avoid bodily injury, remove power from the gate mechanism beforeattempting to remove or replace the gearmotor. The following stepsMUST be taken:1. Position the gate arm of the Mechanism being serviced in thedesired position (See Section 3.2.9),2. Electrically disconnect the Mechanism being serviced byloosening the gold nut on Terminal 5B, and3. Remove and insulate the B12 (or B24) supply wire fromTerminal 2C.2. Disconnect (red and black) power wires from contacts labeled T4 and T5. (For models withmaintenance switch, contacts are labeled T6 and T7.)3. Remove screws from the limit resistor. Temporarily move limit resistor to the side to cleargearmotor when removing.4. Remove pinion gear on output shaft of gearmotor.NOTEPlace your hand under the gearmotor to secure it before removing thelast bolt.SM 6495, Rev. 7, December 2008 3-7