Heat Loss in Electrical Motor

Heat loss from electric motors during operation can be indicated to

Size of Motor (kW)	Heat Loss (Watts/kW)
0 - 2	250
3 - 15	150
15 - 150	100
150 -	80

• 1 kW = 1.34 hp
• 1 hp = 0.746 k W

Alternative - with Imperial Units 

Nameplate Rating	Motor Efficiency Average	Heat Loss to Room Air (Btu per Hr per Rated Hp)
(Hp)		Motor in Room Driven Device inside Room	Motor in Room Driven Devise Outside Room	Motor Outside Room Driven Device inside Room
1/8 to 1/2	0.60	4250	1700	2550
1/2 to 3	0.69	3650	1100	2550
3 to 20	0.85	2950	400	2550

• 1 Btu/h = 0.293 W