Critical Parameters (upper temperature limits)

Enclosure Heat Load Calculations

Drive heat:
W_D = [(HP x 745.7 Watts/HP) / E_M] x (1-E_D) [Watts]

Total heat:
Estimate an additional 25%^a for wire connections and other components.
W_T = W_D x 1.25^a [Watts]

Required airflow:
CFM = (W_T x 3.16) / (T_int - T_amb) [ft.³ / min.]

^aThis is an estimated factor. Further investigation is necessary to obtain actual total heat dissipated in enclosure.

Variables:

Variable Descriptions	Variables	Typical Values

Maximum ambient temperature	T_amb	104 F
Maximum internal temperature	T_int	122 F
Typical temperature rise	(T_int - T_amb)	15 F
Full-load drive power	HP	—
Motor efficiency^b	E_M	.80-.96
Drive efficiency^b	E_D	.96-.98
Drive heat loss	W_D	—
Total heat loss	W_T	—
Required airflow	CFM	—

^bUse full-load efficiency. Motor and drive efficiency will vary based on HP and voltage.

Sample Values:

Drive HorsePower (hp)	Typical Full Load Rating - Motor Efficiency	Typical Full Load Rating - Drive Efficiency	Drive Heat Loss W_D (W)	Additional Heat Loss^a (W)	Total Heat Loss W_T (W)	Airflow when t_int - T_amb = 15 F (CFM)

3	.86	.97	78	20	98	21
10	.90	.97	249	62	311	65
25	.91	.97	615	154	768	162
40	.92	.98	648	162	811	171
75	.93	.98	1203	301	1503	317
100	.94	.98	1587	397	1983	418

^aAdditional Heat Loss - This is an estimated factor. Further investigation is necessary to obtain actual total heat dissipated in enclosure.