General Requirement For Motor Installation

Electric motor is the common application equipment in domestic or industry.If we have a knowledge and good guideline how to selected and install with proper way,It’s can smooth our installation project progress without any problem.

Motor selection and method of installation must suitable with our application to avoid any problem or design error.That why before installation we need have a design review with Electrical & Mechanical Engineer.This time I want share some information about requirement for motor installation that I hope it can gave some basic guideline how to handle motor installation project.


1) Motors shall be suitable for the environment in which they are installed.
2) Motors controlled by Variable Frequency Drives shall be NEMA or IEC inverter-duty rated.

3) Motors shall comply with NEC Article 430 and the requirements of Clause 15 of the EN 60204-1
Motors shall be marked, approved, or listed by a U.S. NRTL (i.e. – UL, CSA, ETL) or an approved 3rd party notified body from the EU (i.e. – TUV, VDE)

4) Where motor nameplates are not clearly visible after installation, a duplicate nameplate shall be located in a clearly visible location.

5) Motors shall be mounted so that proper cooling is ensured and the temperature rise remains within the limits of the insulation class.

6) Guarding shall be provided where surface temperatures of the motor skin exceed 140 degree Fahrenheit / 60 Celsius.

7) Direction arrows shall be installed adjacent and clearly visible to motors where a reverse rotation could produce either an unsafe condition or cause damage to the connected equipment.

8) Motors larger than 75 Hp (55 kW) must have winding Resistance Temperature Detectors, (RTD) and temperature relay to alarm or shut down at high temperature.

electric motor

9) General purpose, 3-phase AC motors shall be energy efficient motors.

10) Efficiency requirements for motors shall adhere to the following:
I) NEMA Requirements covered under EPACT.

II) IEC EFF requirements (IE1-Standard, IE2-High eff, IE3-Premium eff)

11) All motors shall exhibit the electrical performance characteristics of IEC N type, (NEMA design B) motors with a continuous duty rating of S1.

12) A stranded copper insulated ground wire shall be terminated at each motor (Inside the “J” box/ connection box) and originate from the industrial control panel housing the motor starter or Variable Frequency Drive.

13) If special duty motors or other special requirements warrant a deviation from the above specification or if delivery problems occur which will cause a change in the above specification, the P&G Electrical Engineer should be notified.

14) Connections to motors shall be either 1) double crimped ring terminals, bolted and taped or landed directly to the motor-supplied terminal strips. (WIRE NUTS ARE NOT ACCEPTABLE) (Exception is permitted for motors that are designed with integral cable or NEMA (lead) motors.

15) Motor junction boxes must be metal and rated for the installation environment.

16) Motor leads will be continuous from termination to termination. A ground wire shall be run with the motor leads.

17) Motors used in continuous duty applications or in environments that may exceed 40ºC should have a service factor of 1.15 or higher. Such service factor motors will run cooler at rated load which can help extend motor life.



I) AC motors shall be designed for 400 VAC, 50/60 Hz

II) Alternating Current (AC) motors shall be installed with a Variable Frequency Drive.


I) AC motors shall be designed for 460 VAC, 60 Hz

II) Thermal overload protection is required for all non-VFD controlled motors with a power rating greater than ¾ Hp (2.24 kW). Motors below ¾ Hp (2.24 kW) shall have overload protection.


I) AC motors shall be designed for 400 VAC, 50Hz

II) Thermal overload protection is required for all non-VFD controlled motors with a power rating greater than ¾ Hp (2.24 kW). Motors below ¾ Hp (2.24 kW) shall have overload protection.


  1. No. Clue says

    Good day, i am posting here because something’s kind of bothering me about the air conditioning unit we bought. (by the way the reason im posting here is cause i saw a video posted on youtube and it says there to feel free and drop questions at this site, so i am kind of hoping that someone could help me out)
    The brand of the AC unit is Everest not a well known brand in our country.. it’s 1.5hp which was installed 2 days ago in my 11.8 sq.m. room.
    Now before we bought the unit i’ve been reading around the internet that 1.5hp units are used for rooms with 18 to 24sq.m.
    Now im wondering why it doesnt get that cold in my room considering i only have 11.8sq. m. Sure i feel the cold especially when it’s at it’s lowest temp setting but i don’t think that’s the real cooling power of a 1.5hp aircon my room is even tightly sealed and there are no other appliances inside.
    *is it possible that the freon or refrigerant gas is insufficient?
    *or was there any error in installing the unit?
    *or is it because of the brand itself?
    any suggestions or help please?

  2. Hey Lemau,

    What are your thoughts on cast iron ie2 motors? Would you rate them well?


  3. how to install two electric motor using contactors and timers

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