Carrier 50HQP072-120 specifications Sheave Alignment, Unit Size Component Drive Package 50HQP

NOTE: There should be a 3 to 6 mm gap between the mating part hub and the bushing flange. If the gap is closed, the bushing is probably the wrong size.

3.With taper-lock bushed hubs, be sure the bushing bolts are tightened evenly to prevent side-to-side pulley wob- ble. Check by rotating sheaves and rechecking sheave alignment. When substituting field-supplied sheaves for factory-supplied sheaves, only the motor sheave should be changed.

Blower Fan Performance Adjustment — The unit is supplied with variable sheave drive on the fan motor to adjust for differing airflows at various ESP conditions. Select an airflow requirement on the left side of the table, then move horizontally to right under the required ESP for the sheave turns open, rpm and horsepower for that condition. Fully closed, the sheave will produce the highest static capability (higher rpm).

To change fan speeds from factory settings:

1.Shut off unit power supply.

2.Remove belt from motor sheave.

3.Lift motor assembly.

a50-7135tf

Fig. 24 — Sheave Alignment

4.Loosen the 5/16-in. hex nuts on the grommet motor adjust- ment bolts (2 per bolt). To increase the belt tension loosen the top hex nut. To decrease the belt tension loosen the bottom hex nut.

5.Turn the bolts by hand to the desired position then tighten the 5/16-in. hex nuts ( 2 per bolt).

6.Lower the motor assembly.

7.Install the belt.

8.Tension the belt per section below.

9.Restore power to the unit.

BELT TENSION ADJUSTMENT — Using a gage, apply 4 lb of force to the center of the belt and adjust the tension until a deflection of 1/64-in. is achieved for every inch of shaft center distance. See Fig. 25.

Ideal belt tension is the lowest value under which belt slip will not occur at peak load conditions.

LB FORCE

DEFLECTION

a50-7136ef

Fig. 25 — Fan Belt Tension

Table 17 — Blower Sheave and Belt Specifications

UNIT SIZE	COMPONENT		DRIVE PACKAGE
50HQP		A*	B†	C**
	BLOWER SHEAVE	BK67 X 1	BK85 X 1	BK67 X 1
072	MOTOR SHEAVE	1VP34 X 7/8	1VP34 X 7/8	1VP44 X 7/8
	MOTOR HP	1	1	1
	BELT	B X 46	B X 50	B X 48
	BLOWER SHEAVE	BK67 X 1	BK77 X 1	BK62 X 1
096	MOTOR SHEAVE	1VP40 X 7/8	1VP34 X 7/8	1VP44 X 7/8
	MOTOR HP	2	2	2
	BELT	B X 46	B X 48	B X 46
	BLOWER SHEAVE	BK67 X 1	BK67 X 1	BK67 X 1
120	MOTOR SHEAVE	1VP44 X 7/8	1VP34 X 7/8	1VP50 X 7/8
	MOTOR HP	3	3	3
	BELT	B X 48	B X 46	B X 48

*Airflow configurations J, K, N, and P. †Airflow configurations Q, T, U, and V. **Airflow configurations W, X, Z, and 1.

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