BaldorM3557Three-Phase TEFC General Purpose Motor, 1.5 HP, 1140 RPM, 208-230/460 V, 56H Frame, Design B

Product Description

What this part is

Baldor M3557 three-phase general purpose AC induction motor. Manufacturer: Baldor. Part Number: M3557. Horsepower: 1.5 HP. Synchronous Speed Class: 1200 RPM, six pole. Full Load Speed: 1140 RPM. Phase: 3. Frequency: 60 Hz. Voltage: 208-230/460 V. Full Load Amps: 5.0 to 4.9 A at 208-230 V, 2.45 A at 460 V. NEMA Frame: 56H. Enclosure: TEFC, totally enclosed fan cooled. Mounting: foot mount with standard flange. NEMA Design: B. Service Factor: 1.15. Insulation Class: F. Efficiency at Full Load: 80 per cent. Full Load Torque: 6.97 lb-ft. Breakdown Torque: 23.6 lb-ft. Frame Material: steel. Ambient Temperature Rating: 40 °C. Bearing Grease: Polyrex EM. Manufacturer Status: discontinued.

Decoding the designation

M — Baldor’s general purpose three-phase motor prefix.

3557 — the catalogue number that fixes the 1.5 HP rating, the 1140 RPM six-pole speed and the 56H frame.

M-3557 and M3557 are the same catalogue number, hyphenated and plain.

What these specs mean in practice

Horsepower: 1.5 HP. Full Load Speed: 1140 RPM. Full Load Torque: 6.97 lb-ft. A six-pole 1140 RPM motor turns at two thirds the speed of a common four-pole machine, so at the same horsepower it delivers half again the shaft torque, which is why 1200 RPM class motors are specified on augers, mixers, conveyors and fans where speed reduction would otherwise be needed. Breakdown Torque: 23.6 lb-ft. Breakdown torque is 3.4 times the full load figure, which is the margin available to pull through a momentary jam. NEMA Design: B. Design B is the standard-torque, standard-starting-current curve that most across-the-line starters and drives are sized for. Service Factor: 1.15. A 1.15 service factor means the motor is rated to run continuously at 15 per cent above nameplate horsepower, giving 1.725 HP of headroom on the same frame. Insulation Class: F. Ambient Temperature Rating: 40 °C. Enclosure: TEFC. A totally enclosed fan cooled frame keeps dust, chips and washdown spray out of the windings and cools through the shell, which is the standard choice for a motor sitting in the open on a plant floor. Efficiency at Full Load: 80 per cent.

Mounting data

NEMA Frame: 56H. Mounting: foot mount, standard flange. Frame Material: steel. The 56H frame is the extended-base 56 frame: it carries a second set of foot holes so the motor bolts onto either a 56 or a 143T/145T footprint without a new base plate.

Quantity and configuration

Unit Quantity: 1 Pc. One complete motor per listing.

Condition

Condition: Used, old stock. Photographs on the listing show the motor as it stands.

Interchange guidance

M3557 and M-3557 are the same catalogue number. Manufacturer Status: discontinued, so the M3557 is a replacement-market number rather than a current catalogue item. Within Baldor’s general purpose range the 3557 catalogue figure carries the 1.5 HP, 1140 RPM, 56H combination across prefixes: CM3557 is the C-face execution and VEM3557 the vertical, both on the same electrical rating.