Bryant 558D B. Belt Drive Motors, C.Ventilation Sequence, Ð Belt-DriveMotor Mounting

Table 18 Ð 558D072 Air Delivery Ð Horizontal Discharge Units (Standard Motor)

												STANDARD BELT DRIVE MOTOR
AIRFLOW												External Static Pressure (in. wg)
(Cfm)		0.1			0.2			0.4			0.6			0.8		1.0			1.2			1.4				1.6
	Rpm		Watts	Rpm		Watts	Rpm		Watts	Rpm		Watts	Rpm		Watts	Rpm	Watts	Rpm		Watts	Rpm		Watts		Rpm		Watts
1800	765		487	821		532	923		638	1019		843	1099		883	1178	1031	1249		1182	1316		1353		1382		1526
1900	802		539	854		585	953		700	1046		835	1126		965	1201	1106	1274		1275	1338		1439		1402		1621
2000	840		600	888		646	984		771	1073		907	1154		1047	1226	1990	1297		1361	1363		1534		1424		1718
2100	878		669	923		716	1015		843	1101		981	1182		1140	1252	1292	1320		1456	1388		1639		1448		1831
2200	916		739	958		795	1046		924	1129		1072	1209		1241	1280	1404	1345		1569	1410		1744		1473		1945
2300	954		827	993		883	1079		1022	1160		1173	1237		1344	1309	1517	1372		1691	1434		1866		1496		2067
2400	993		916	1029		973	1112		1123	1190		1275	1264		1447	1336	1639	1400		1823	1459		1997		1519		2188
2500	1031		1022	1066		1081	1145		1241	1220		1396	1292		1569	1363	1770	1428		1962	1486		2145		1543		2335
2600	1070		1131	1103		1199	1179		1353	1251		1517	1322		1700	1390	1901	1456		2102	1514		2300		1569		2487
2700	1109		1258	1140		1318	1212		1482	1283		1656	1352		1849	1418	2041	1483		2257	1543		2462		Ð		Ð
2800	1148		1396	1177		1465	1246		1621	1316		1805	1383		1997	1446	2188	1510		2403	Ð		Ð		Ð		Ð
2900	1188		1543	1215		1604	1281		1770	1349		1962	1413		2154	1476	2352	1537		2562	Ð		Ð		Ð		Ð
3000	1227		1700	1253		1770	1316		1936	1382		2136	1444		2317	1506	2529	Ð		Ð	Ð		Ð	Ð		Ð

NOTES:

1.Boldface indicates ®eld-supplied drive required. (See Note 7.)

2. indicates ®eld-supplied motor and drive are required.

3.indicates maximum usable watts of a factory-supplied motor.

4.Maximum usable watts input is 2120. Extensive motor and electrical testing on these units ensures that the full range of the motor can be utilized with con®dence. Using your fan motors up to the wattage ratings shown will not result in nuisance tripping or premature motor failure. Unit warranty will not be affected. For additional information on motor performance, refer to Table 4.

5.Values include losses for ®lters, unit casing, and wet coils.

6.Use of a ®eld-supplied motor may affect wire sizing. Contact your distributor to verify.

7.Standard motor drive range: 1070 to 1460. All other rpms require ®eld-supplied drive.

8.To convert watts to bhp:

bhp =

watts input x motor efficiency

746

Motor efficiency = .84

B. Belt Drive Motors

Fan motor pulleys are factory set for speed shown in Table 1.

To change fan speed:

1.Shut off unit power supply.

2.Loosen belt by loosening fan motor mounting nuts. See Fig. 34.

3.Loosen movable pulley ¯ange setscrew (see Fig. 35).

4.Screw movable ¯ange toward ®xed ¯ange to increase speed and away from ®xed ¯ange to decrease speed. Increas- ing fan speed increases load on motor. Do not exceed maxi- mum speed speci®ed in Table 1.

5.Set movable ¯ange at nearest keyway of pulley hub and tighten setscrew. (See Table 1 for speed change for each full turn of pulley ¯ange.)

To align fan and motor pulleys:

1.Loosen fan pulley setscrews.

2.Slide fan pulley along fan shaft.

3.Make angular alignment by loosening motor from mounting.

To adjust belt tension:

1.Loosen fan motor nuts.

2.Slide motor mounting plate away from fan scroll for proper belt tension (1¤2-in. de¯ection with one ®nger).

3.Tighten motor mounting nuts.

4.Adjust lock bolt and nut on mounting plate to secure motor in ®xed position.

C.Ventilation Sequence

If unit is equipped with economizer, the damper will open to the minimum position whenever the evaporator fan runs.

MOTOR MOUNTING

NUTS AND BOLTS

Fig. 34 Ð Belt-Drive Motor Mounting

Fig. 35 Ð Evaporator-Fan Pulley Adjustment

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