Baldor 9C, 11C instruction manual Maintenance, Overload Protection, Thermal Capacity

MAINTENANCE

For average industrial applications involving 3 or 4 starts a day of not more than 6 seconds acceleration time each, the flow charge should be changed every 10,000 hours of operation. For more severe conditions, visually inspect flow charge at more frequent intervals; it should be changed when it has deteriorated to a half powder, half granular condition. Visual inspections should continue until enough flow charge changes have been made to adequately establish a schedule for renewing FLEXIDYNE flow charge.

The FLEXIDYNE has been lubricated at the factory and no further lubrication is required. Never apply grease, oil or any other foreign material to the flow charge.

OVERLOAD PROTECTION

A Thermal Cutout is available from Dodge and is recommended for FLEXIDYNE Size 9 where slippage (due to overloads, starting or reversing) is frequent or prolonged. Its function is to protect against excessive heat which may be generated by the FLEXIDYNE, A Speed Drop Cutout is available from Dodge for FLEXIDYNE Size 11 for installation where overloads or jamming may occur.

Either unit can be installed to send a signal to interrupt the motor current and, if desired, activate a bell, light or other warning device. Cutout switches are intended for use in control circuits only and are not recommended for dc current nor should they be used directly in the line to the motor. Both units are available in special explosion- proof models for hazardous atmospheres.

THERMAL CAPACITY

Since there is slippage within the flow charge during acceleration, heat is generated from friction. The thermal capacity of the FLEXIDYNE is based on balancing this heat generated during acceleration against the cooling time between accelerations. The amount of heat generated is determined by the amount of horsepower dissipated by slipping and the duration of each acceleration. If the flow charge weight is light, the heat generated will not be as great as that which would be generated with a heavier flow charge, when compared at

the same acceleration time. A longer time between starts will dissipate more heat; therefore, higher starting horsepowers may be transmitted, or longer acceleration times may be allowable. (See Starting Cycle)

Acceleration times shown in Table 1 are for starting frequencies of one start per hour or less. If starting frequency is more than once per hour, use acceleration time for actual starting cycle shown in Table 2.

Acceleration times listed in Tables 1 & 2 are the MAXIMUM permissible for the various starting frequencies listed. The MINIMUM acceleration time required for proper FLEXIDYNE operation is 1 to 1½ seconds. This is the time required for the flow charge to be uniformly distributed around the housing cavity before the unit "locks in". Any acceleration time between the minimum and maximum listed is acceptable, although a shorter acceleration time will generally provide longer wear life. For applications requiring a specific acceleration time (within these limits) flow charge may be added or removed to produce the required results.

Stalled – If a jam-up stalls the drive, the motor continues to run and the FLEXIDYNE slips. This causes heat to be generated at twice the rate of normal acceleration. Therefore, the allowable slipping time, when stalled, is half the allowable acceleration time given in Table 1.

Starting Cycle is the time from the beginning of one acceleration to the beginning of the next. Allowable acceleration times in Table 2 are based on the assumption that the FLEXIDYNE will be running continuously except for a momentary stop before the next start. If the stop is more than momentary, decrease the actual starting cycle by one-half the stopped time before using Table 2; far example, with a 50 minute actual starting cycle of which 20 minutes is stopped time, decrease 50 by half of 20 to give 40 minutes as the starting cycle time to use for Table 2.

Grouped Starts –For several starts grouped together followed by uninterrupted running, add the acceleration times of all starts and consider it as the time for one start. The starting cycle would be the time from the beginning of one group of starts to the beginning of the next group.

Table 1 – Flow Charge Recommendations

Based on % of Starting Torque for 1760 RPM NEMA Design B Motors

			100%	@ 1760 RPM					125% @ 1750 RPM					150%	@ 1740 RPM					175% @ 1700 RPM					200% @ 1650 RPM
Rated	FLEXI-	Start-			Flow		Max.	Start-		Flow		Max.	Start-			Flow		Max.	Start-		Flow		Max.	Start-		Flow		Max.
				Charge			Time		Charge			Time			Charge			Time		Charge			Time			Charge		Time
Motor	DYNE	ing						ing					ing						ing					ing
HP	Size	HP	Lbs.			Oz.	In	HP	Lbs.		Oz.	In	HP	Lbs.			Oz.	In	HP	Lbs.		Oz.	In	HP		Lbs.	Oz.	In
							Sec.					Sec.						Sec.					Sec.					Sec.
15	9C	15.0	2			9	76	18.8	3		0	58	22.3	3			7	58	25.5	3		13	39	28.3		4	2	28
20	9C	20	3			2	52	25	3		10	40	30	4			0	26	34	4		8	22	38		5	3	16
25	11C	25	4			3	98	31	4		12	76	37	5			0	55	42	5		8	42	47		6	2	37
30	11C	30	4			10	80	37	5		0	55	45	5			12	39	51	6		3	33	57		6	12	27
40	11C	40	5			5	44	50	6		0	34	60	6			8	24	68	7		3	22	75		8	0	19
50	11C	50	5			13	34	62	6		10	24	74	7			6	20	85	8		2	17	94		8	11	15

872-3

4