NEMA Standard Premium Efficiency Three Phase Induction Electric Motor

Our motors are three phase induction electric motors which are single speed, totally enclosed, self-ventilated, continuous duty, low voltage and cage type. They conform to NEMA MG1 Standard, and the whole series adopt casting iron frames. The efficiency meets America NEMA EPACT Standard. The service factor is 1.15 or 1.25. The motors have obtained American CC Certification and Canadian CSA Certification.

These series motors are insulation grade F and the protection level is IP54 (IP55). The voltage class is 230/460 V，460V or 575 V, the rated frequency is 60 Hz, the ambient temperature range is -15-40℃, and the altitude is no more than 3300 feet. They are suitable for situations without special requirements and can be matched with the power of various mechanical equipments.

NEMA Frame Number Suffixes

You’ll notice a letter suffix after the NEMA frame number and it, too, has been standardized by NEMA regulations. These suffixes provide key information about the motor, how it is mounted, what its purpose is, what type of shafts it has, and more. Here is a summary of what the suffixes mean:

C: type C face mounting on DE
D: type D flange mounting on DE
H: designated 56H motors have two sets of 2F mounting holes, 3 in. and 5 in.
J: NEMA C face mount, threaded shaft pump motor
JM: face-mounted, close-coupled pump motors with specific dimensions and bearings
JP: type C face-mounted, close-coupled pump motors with specific dimensions and bearings
K: has a hub for sump pump mounting
LP or LPH: type P flange-mounted, vertical solid-shaft motors
M or N: flange mount for oil burner motors (6 3/4” flange for M, 7 1/4” flange for N)
P or PH: type P flange-mounted vertical hollow-shaft motors
R: drive end tapered shaft connection
S: Standard short shaft for direct connection
T: standard dimensions for this frame designation have been established
V: vertical mounting only
VP: type P-flange mounted, vertical solid shaft motor
X: wound-rotor crange motor with a double shaft extension
Y: special mounting dimensions, contact manufacturer for details
Z: all mounting dimensions are standard except the shaft dimensions OR used to designate double shaft extensions, but in either case contact the manufacturer for details

NEMA Standard Enclosures

NEMA designates certain enclosure types for motors and divides them into two categories: open machines and totally enclosed machines. What follows are descriptions of the NEMA standard enclosures that you are most likely to encounter.

Basic NEMA Motor Configurations

There are three commonly used NEMA motor configurations: standard duty/general purpose, severe duty, and IEEE 841 Motors. They intended for different applications and, as a result, usually have different types of enclosures, bearings, and appropriate work environments.

Standard Duty or General Purpose Motors

Standard duty or general purpose motors are most often ODP or TEFC motors and are manufactured to meet NEMA premium efficiency regulations. These motors will most likely have either ball bearings or roller bearings if they are intended for an application with a belted high radial load. They are not appropriate for use in harsh, dirty environments.

Severe Duty Motors

Severe duty motors only have TEFC enclosures. They are made for tougher applications and harsh environments such as chemical processing, mining, foundry, pulp and paper, waste management and petro/chemical applications.

NEMA Motor Insulation Classes

There are also NEMA motor insulation classes that describe the ability of a motor’s winding to withstand heat. The four most common classes are listed below and they specify the allowable rise above a 40°C ambient temperature.

Class A:

Maximum Temperature Rise: 60°C,
Hot-spot Over Temperature Allowance: 5°C
Maximum Winding Temperature: 105°C

Class B:

Maximum Temperature Rise: 80°C
Hot-spot Over Temperature Allowance: 10°C
Maximum Winding Temperature: 130°C

Class F:

Maximum Temperature Rise: 105°C
Hot-spot Over Temperature Allowance: 10°C
Maximum Winding Temperature: 155°C

Class H:

Maximum Temperature Rise: 125°C
Hot-spot Over Temperature Allowance: 15°C
Maximum Winding Temperature: 180°C

NEMA standards are an important way to specify the type of motor that you need and to evaluate the suitability of a motor for your application. These standards cover key factors ranging from size and suitability to enclosures and even winding insulation. If you have any questions about NEMA standards for electric motors, the experts here at HECO would be glad to assist you.

NEMA Standard Premium Efficiency Three Phase Induction Electric Motor Applications:

Ventilation Fans Motors
Blowers Motors
Pumps Motors
Compressors Motors
Motors For Plastic Injection Machines
Machine Tools Motors
Motors For Stone Machinery
Conveyors Motors
Crushers Motors
Stirring Motors
Agitators Motors
Motors For Reciprocating Pumps
Motors For Punch Presses
Motors For Pilling Machines
Elevators Motors
Extractors Motors
Winches Motors
Hoists Motors
Wire-drawing Motors

NEMA Standard Premium Efficiency Three Phase Induction Electric Motor Terminal Box

Terminal box is seated in the middle of the frame. The motor has 3, 6, 9, 12 outgoing lines. The following figure shows the connections. Terminal markings and connection diagram is in accordance with MG1-2.62 provisions. There are ground connection marks and bolts in the terminal boxes.