MARS 10587 – Furnace Blower Motor, 1/2 HP, 115/1/60, 1,075 RPM, 3 Speed MARS direct drive furnace blower motors are three speed standard efficiency models. All models are electrically reversible and include 2 1/4 inch resilient rings for base mounting. These models have all angle sleeve bearings and have open air over enclosures. 1/2 inch extended thru bolts. 2 1/4 inch resilient rings. Single phase, 60 Hertz. Fan duty, continuous, air over. California residents: see Proposition 65.