Starter selection can be straight forward if the terminology is the same.  An attempt to clarify some of the common components is what you will find in this section.  If there are any additional questions, please do not hesitate to call or e-mail any of us in the shop for further clarification.















EMSCO, The Motor Control Shop                 The Motor Control Shop, inc.


If your question is not covered here... call or e-mail us for the answer!!!

Click here to take you to the STARTER SIZING CHART.

  • Starter Sizing
  • Heater/Overload chart
  • Breaker sizing
  • Fuse sizing
  • Wire Sizing


Click here to view the Control Power Transformer fusing chart   (Dual Primary/Single Secondary)   


Click here to view/search all the EATON Cutler Hammer Catalogs  


Why do you need a motor starter? (a couple of basic reasons/explanations)

A starter is made of 2 main components; a contactor and an overload.

Starting a motor generates a large in-rush of electricity and closing of the gap of the power circuit can generate a violent arc of electricity. The contactor portion of the starter closes the contacts on all phases of the current very quickly and positively, minimizing the damaging/dangerous arc. The contactor also has protective shielding to help contain this arc. The same condition can occur when the motor is turned off. Starters have contacts that are made of very strong, durable materials to provide many years of safe starting and stopping of motors. Starters are sized to the motor/voltage. (see the starter sizing chart and heater overload charts (link at top of this page)

Starters also have an overload protective device that can monitor the load or amperage draw that he motor is consuming. This device is sized or set to a pre-determined maximum load the motor can safely handle. When a condition occurs that the motor exceedes the set load, the overload device opens the motor starter control circuit and the motor is turned off. Overloads come in a variety of types including a small heating type elements or solid state electronic devices. The starter is a protection device for the motor. These overloads can also monitor for phase loss and single phase conditions.

Starters can be turned on by much lower (safe) control voltages. For example a starter controlling a 480V 3 phase motor can be turned on by a 24v thermostat. This provides a safe voltage for the remote devices such as switches, pilot lights, thermostats etc....By using low voltage control circuits, many small devices can be added to a motor starter to enable it to control or be controlled by simple to complex computer based systems. A good example would be a building energy management system can easily control many starters.

EMSCO intigrates many low voltage devices into it's starters and can design and build starters to manage many aspects of complex motor operation, such as complex cooling tower applications.


What information do you need to give us to Order a STARTER ?

1.  Horsepower of the motor

                    Check the name plate that is attached to the side of the motor.

2.  Primary voltage (motor voltage)

                     Voltage that the MOTOR is powered by.

3.  Full load amperage draw of the motor.

                    Need this to order the proper heater (overload protection) for the starter.   

                ** Multi-speed motors will have multiple amperage draw demands  **            

4.  Control circuit voltage

                    What is going to turn the starter on or off?  Is this device remote?  Is this device capable of high (line voltage of 208 or 460)?

                    These answers will determine whether a CPT or Control Power Transformer is needed to reduce the control voltage.

5.  Combo or Non-combo

                        With disconnect -> Combo

                        Without disconnect -> Non-Com

6.  Fused power circuit or non-Fused

                        To be more specific, does the starter need to be fused or non-fused?  

                                 Is the branch circuit feeding the starter already on a properly sized fuse or breaker?  If not, the starter must be fused.


7.  Type of enclosure - Where is the starter being installed. (More detail below)

  •   NEMA 1 - Standard indoor enclosure

  •   NEMA 3R - Standard Raintight enclosure

  •   NEMA 4X - 304 Stainless steel - for food service, extended exterior use, mild corrosive environment.

  •   NEMA 4x - 316 Stainless Steel - SPECIAL ORDER - for very corrosive environments such as sewage and water treatment facilities.

  •   NEMA 12 -  Standard steel enclosure, sealed to be dustproof.  All holes must be drilled and sealed on site.

   8.  Accessories for your starter.

         Control what type of switch or control device do you want mounted on/in the starter?

                                    Examples of controls with custom label plates.

  • HOA (Hand-Off-Auto) switch or push buttons to turn on the starter, either in manual or hand mode or automatic mode or remote control.

  • Start-Stop           

  • On-Off          

  • Motor Run Motor Stop

  • High-Low-Off-Automatic

  • Forward Off - Reverse


Indicator lights OPTIONAL - what type of pilot lights (or colors) do you want to turn on to indicate what devices are on or off.

                        Indicator lights are labeled with custom label plates identifying the function of the pilot light.


  • Phase protection

  • Timer controls

  • Additional auxiliary switches to control additional devices.

  • Relays

  • Terminal strip

  • Custom control interface

  • Temperature Controls


 What is a COMBO starter?

   Click here for a graphic description.

    A starter in an enclosure that has a disconnect switch incorporated in the front of the enclosure.

What is a NON-COM or NON-COMBO starter?

   Click here for a graphic description.

  A starter in an enclosure that has NO disconnect switch or fusing. 

Why would I need an OVERSIZED (E3) enclosure?

  Typically an oversized enclosure is needed when multiple devices are added to an enclosure.  Various electrical codes require minimum wire spacing or wire bending spacing and when multiple devices are installed in an enclosure, a larger enclosure is necessary to meet code.


A couple more important HOW TO's.

How to know when you need to replace starter contacts.   

How to wire an A200 series starter (old Westinghouse starters/contactors/lighting contactors)




Enclosure Types
Enclosures provide mechanical and electrical protection for operator and equipment. Brief descriptions of the various types of enclosures offered by Cutler-Hammer are given below. See NEMA Standards Publication No. 250 for more comprehensive descriptions, definitions and/or test criteria.

NEMA Type 1 (Conforms to IP40) for Indoor Use
Suitable for most applications where unusual service conditions do not exist and where a measure of protection from accidental contact with enclosed equipment is required. Designed to meet tests for rod entry and rust resistance. Enclosure is sheet steel, treated to resist corrosion. Depending on the size, knockouts are provided on the top, bottom and sometimes on the side.

NEMA Type 3R (Conforms to IP52) for Outdoor Use
Primarily intended for applications where falling rain, sleet or external ice formations are present. Gasketed cover. Designed to meet tests for rain, rod entry, external icing and rust resistance. Enclosure is sheet steel, treated to resist corrosion. Depending on the size, a blank cover plate is attached to the top (for a conduit hub) and knockouts are provided on the bottom. Cover-mounted pilot device holes are provided and covered with hole plugs.

NEMA Type 4 (Conforms to IP65) for Indoor or Outdoor Use
Provides measure of protection from splashing water, hose-directed water and wind blown dust or rain. Constructed of sheet steel with gasketed cover. Designed to meet tests for hose-down, external icing and corrosion protection. Enclosure has two water- tight hubs (power) installed top and bottom of one control hub installed in bottom - depending on size. Cover-mounted pilot device holes are provided and covered with hole-plugs.

NEMA Type 4X (Conforms to IP65) for Indoor or Outdoor Use
Provides measure of protection from splashing water, hose-directed water, wind blown dust, rain and corrosion. Constructed of stainless steel with gasketed cover. Designed to meet the same tests as Type 4 except the enclosure must pass a 200-hour salt spray corrosion resistance test.

NEMA Type 7 for Hazardous Gas Locations
For use in Class I, Group C or D indoor locations as defined in the National Electrical Code. NEMA Type 7 enclosures must withstand the pressure generated by explosion of internally trapped gases and be able to contain the explosion so that gases in the surrounding atmosphere are not ignited. Under normal operation, the surface temperature of the enclosure must be below the point where it could ignite explosive gases present in the surrounding atmosphere. Designed to meet explosion, temperature and hydrostatic design tests.

NEMA Type 9 for Hazardous Dust Locations
For use in Class II, Group E, F or G indoor locations as defined in the National Electrical Code. Heat generating devices within the enclosure are designed to maintain the surface temperature of the enclosure below a point where it could ignite the dust-air mixture in the surrounding atmosphere or cause discoloration of surface dust. These enclosures are designed to meet tests for dust penetration, temperature and aging of gasket (if used).

NEMA Type 12 (Conforms to IP62) for Indoor Use
Provides a degree of protection from dripping liquids (non-corrosive), falling dirt and dust. Designed to meet tests for drip, dust and rust resistance. Constructed of sheet steel. Hole plugs cover pilot device holes. There are no knockouts, hub cover plates or hubs installed. Many Cutler-Hammer NEMA Type 12 enclosures are suitable for use in Class II, Division 2, Group G and Class III, Divisions 1 and 2 locations as defined in the National Electrical Code.

NEMA Type 12 Safety Interlock
The Type 12 enclosure can be ordered with a safety interlock on the door that can be padlocked off. A vault-type door latch system is used. A tapered plate holds the gasketed door tight against the case edge to provide a positive seal. The special door interlock consists of the door handle and a screwdriver operated cover defeater. The cover defeater and the disconnect interlock defeater are both recessed screwdriver operated devices which cannot be anipulated with other types of tools.




The new lighting contactors can be a little difficult to figure out, so here are 2 quick photos to show how to wire the mechanically held lighting contactors.  

2 wire and 3 wire control diagrams.

lighting contactor, 2 wire control

lighting contactor, 3 wire control



EATON / CUTLER HAMMER CUT SHEETS  can be obtained by searching the published catalog pages by EATONThere is also an alternate catalog selection page.    Links to both catalog sections are always available on the EMSCO.net home page.





 email: jody@emsco.net
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