Stearns 1-048-161 General Installation Notes, II. Installation Procedure, III. Torque Adjustment

pressure spring force against the stationary plate and friction disc, stopping and holding the load.

Warning! Any mechanism or load held in position by the brake should be secured to prevent possible injury to personnel or damage to equipment before any disassembly of the brake is attempted or the manual release lever is operated on the brake.

When the motor is off and the load is to be moved without energizing the motor, the manual release lever can be rotated 90° away from the mounting face. This removes the retarding torque from the motor shaft, allowing the load to be moved. The brake will remain in the manual release position until the release lever is returned manually to its set position, or until the brake is re-energized electrically and the release lever returns to its set position automatically.

Note: The motor should not be run with the brake in the manual release position to avoid overheating of friction disc.

I. General Installation Notes

Brake mounting can be in any position. Brake is mounted with two 1/4” flat head socket cap screws mounted 180° apart.

II. Installation Procedure

1.Remove housing nuts (15) and housing

(7) or (7A).

2.Remove hub (16) from brake and slide onto motor shaft and key (not furnished) to within 3/16” of motor mounting surface. Torque both set screws to 33 lb-in of torque.

Note: Check motor mounting face to be sure NEMA dimensions of 0.004” T.I.R. on concentricity and face run out are met. Shaft run out is to be within 0.002” T.I.R. Maximum shaft end float is 0.020”.

3.Attach brake to mounting surface by sliding the brake friction disc (4) onto hub (16), engaging without force. Brake endplate (2) is to be tight against mounting face.

4.Mounting the brake to the mounting surface with two 1/4” flat head socket cap screws (not furnished). Notches are provided in the friction disc for accessibility to the mounting holes. Torque to screw manufacturer’s recommendation based on materials being used. Screw heads may not protrude above wear surface. Brake mounting can be in any position.

5.Verify solenoid air gap is 1/8”. Push in plunger and allow it to snap out. Check air gap. For vertical above motor mounting, see Note in Wear Adjustment Section. If adjustment is required, see Wear Adjustment.

6.See Electrical Connection for coil connection.

7. Replace housing.

III. Torque Adjustment

The brake is factory set for nominal rated torque. No further adjustment to increase torque may be made. The approximate compressed torque spring length to produce nominal rated torque is given in Table A.

Table A

	Brake Torque	Length “L”
	(lb-ft)	(in.)
1.5		1
3		15/16
6		1-1/8

1-1/2 and 3 lb-ft

6 lb-ft

Figure 2

To increase stopping time on 3 and 6 lb-ft brake, turn torque adjusting nuts (18) counterclockwise equal amounts to increase spring length. Spring studs equipped with flats on the end are for a wrench if the studs loosen during torque adjustment. For the 3 and 6 lb-ft brakes, one full turn on the nut will reduce the nominal torque approximately 15%. Do not reduce torque to less than 50% of nominal rated. Torque for the 1.5 lb-ft brake may not be reduced.

IV. Electrical Connection

CAUTION 1: Inverter Motor and Special Control Systems. This brake contains either a single phase AC coil or DC coil that requires instantaneous power within

±10% of rating at the coil. A separate power source is required when this brake is used in conjunction with a motor or control system that limits voltage or current input (i.e. inverter motors) or causes a ramping of the power supply.

CAUTION 2: Class H coils with terminals. Do not bend lead wire crimp connection as this causes a fatigue in the metal which may break under vibration.

Note 1: Brake coil connections described here cover common motor connections. For nonstandard motor or control

connections contact respective supplier or Stearns Division.

Note 2: Be sure lead wires to coil are not tight or pinched, and that leads will not be rubbed by friction disc, trapped between solenoid plunger and frame, caught between lever arm and endplate, or by linkage.

General

All coils are single-phase alternating current (AC).

Single voltage coil connection

Connect coil (12C) to any two wires of a single-phase or three-phase power source of appropriate voltage. For operation with a motor control, connect to any two motor leads with correct voltage.

Dual voltage coil connection

Preconnect coil for appropriate high or low voltage as shown in Figure 3. On these coils observe the lead numbering sequence for proper connections as follows:

For	Power Line A	Power Line B	Tie Leads
Low voltage	1 and 3	2 and 4	–
High voltage	1	2	3 and 4

Figure 3

Connecting AC solenoid coils on dual voltage 230/460 three-phase motors

To use a 230 volt coil (or a 230/460 dual voltage coil connected for 230 volts) with a 230/460 dual voltage three-phase motor, the brake leads are connected across two motor terminals as shown, or other equivalent combinations. If a 230 volt brake coil is connected as shown in Figures 4 or 5, the motor can be operated on either 230 volts or 460 volts with no effect on brake operation.

Figure 4 Figure 5

V. General Maintenance

1.Warning! Any mechanism or load held in position by the brake should be secured to prevent possible injury to