103 IEC Starters Selection Guide
IEC Motor Starters Overview
IEC starters are electrically operated switches that start and stop electric motors safely. Like relays, motor starters switch the motor power ON/OFF, but unlike relays, they can reverse the direction of the motor and provide low voltage and overcurrent protection.
IEC-style motor starters are modular and more flexible. They include a control unit and power base in a modular format and an adjustable overload relay assembly. In general, IEC-rated starters are smaller, less costly, and more application-specific than NEMA-rated motor starters, which are larger, more expensive, and more robust in design. Usually, an IEC-style starter is almost half the size of a NEMA-style starter of the same current rating. However, for current ratings above 100 Amperes, the physical differences between the NEMA and IEC starters are negligible.
In addition, most IEC starter sizes allow users to match the starter to a particular application conveniently. Unlike the NEMA-style starters, available in standard sizes across the industry, the size ratings of IEC starters vary by manufacturer. This article acts as a detailed guide to selecting the right Allen-Bradley 103 IEC motor starter for any application. But first, let’s do a quick brush-up on the types, components, mode of operation, and fundamental functions of motor starters.
Types of Motor Starters
Motor starters can be classified in various ways, for example, starting techniques, number of components, switching mechanism (manual or automatic), enclosure type (open or enclosed), etc. But the two most basic types of motor starters are:
A) Manual Starters
These electro-mechanical devices have an overload relay and an ON/OFF mechanical switch. They include a push button, toggle switch, or rotary knob directly mounted on the starter. The connected motor is turned ON or OFF by pressing the button or turning the knob/toggle switch. Mechanical linkages from the toggle switch/button or rotary knob force the contacts of the starter unit to close and open, thereby making or breaking the starter’s power circuit to start or stop the connected motor.
Manual starters allow users to switch electric motors ON/OFF manually. They also provide fuseless protection against overload conditions, phase failures, and short-circuit faults. However, in case of a power failure, these starters do not break the control circuit of the motor. Thus, they can be dangerous in critical systems because the controlled motor automatically restarts when the power supply is restored. Manual starters are available in both IEC-style and NEMA-style configurations and in NEMA standard sizes.
B) Magnetic Starters
Magnetic starters are available as either IEC or NEMA-certified and in NEMA standard sizes.
Let’s discuss the components, mode of operation, and examples of magnetic starters because they are the most common types of starters used in electric motor applications to initiate/stop operation and provide overload protection safely.
Components of a Magnetic Motor Starter
All magnetic motor starters include two main elements that complement one another to control and protect the connected motor. The two components are:
- Contactor: This is an electrically controlled switch whose primary function is to allow or restrict current flow to an electric motor. It switches the supply voltage to the motor ON or OFF. The contactor includes an electromagnetic coil and different types of contacts, namely power contacts, contact springs, and auxiliary contacts, each with an individual role. For instance, the power contacts carry an electric current to the starter-controlled motor. The electromagnetic coil provides the driving force (i.e., electromagnetic force) needed to close the power contacts. A protective enclosure houses the electromagnetic coil and multiple contacts.
- Overload Relay (OLR): This is a relay switch that opens the power circuit of an electric motor in the event of a thermal, power, or electrical overload. In doing so, it prevents the motor from drawing excessive current or overheating, consequently protecting it against potential damage resulting from the two scenarios. The overload relays used in motor starters include a heater element and a set of Normally Closed (NC) contacts, which only open when they experience an overload condition. The heater component is connected in series with the main power line to an electric motor. As such, all the current the motor draws passes through the heater. In magnetic starters, the Normally Closed contacts of the OLR are wired in series with the contactor’s electromagnetic coil. In manual starters, those contacts are wired in series, with the main power line feeding the motor.
Mode of Operation
A typical magnetic motor starter has two circuits, which are:
- Power Circuit: The power circuit of a magnetic starter transmits the line voltage to the connected motor through the overload relay and the main contacts of the contactor.
- Control Circuit: This circuit operates the contactor’s electromagnetic coil, energizing or de-energizing it. As mentioned earlier, the primary power contacts of the contactor are in charge of allowing or restricting current flow to the motor. To accomplish this, the power contacts need to be in a Closed or Open position. The starter’s control circuit provides a control voltage that energizes the electromagnetic coil to create an electromagnetic field. The generated electromagnetic field pulls the power contacts of the contactor to a closed position. This completes the power circuit between the main supply line and the connected motor, allowing current flow to the motor. When the control voltage is removed, the electromagnetic coil is de-energized, and the contactor’s power contacts return to an open position. This interrupts the power circuit, disconnecting the motor from the power line.
Examples of Magnetic Motor Starters
A) Full Voltage, Non-Reversing Starters
Full Voltage Non-Reversing (FVNR) starters operate electric motors across the main power line for the applied voltage in just one rotational direction. They allow the full line voltage to be applied to the connected motor. They can thus be thought of as Across-the-Line (ATL) magnetic starters.
These motor starters comprise a magnetic contactor, overload protection device, control circuit transformer c/w fusing, Start/Stop operators, and run/fault indicator lights. They use short-lived contact pilot devices such as push buttons, float switches, selector switches, limit switches, etc., connected to the contactor’s electromagnetic coil to execute the start and stop functions. The control power transformer steps down incoming line voltage into a lower, safer voltage for the control circuit.
Note, the FVNR motor starters do require a restart after a low voltage or power failure condition causes the magnetic contactor to drop off. An example of a Full Voltage Non-Reversing magnetic starter is the Direct-On-line (DOL) starter described below: Direct-On-Line (DOL) Starter The DOL starter includes an overload relay, a circuit breaker, and a contactor with an electromagnetic coil. The control circuit of this starter includes two separate Start and Stop Push Buttons, but other types of controls, such as a float switch, limit switch, selector switch, etc., may be used.
Pressing the Start Push Button energizes the contactor coil to close the contactor’s main contacts, thereby completing the power circuit between the main supply line and the connected motor. This allows the supply current to flow to the motor, turning it on. The Stop Push button is provided to turn the motor off.
To protect the connected motor from overheating and overcurrent conditions, the control circuit of the DOL starter is wired through a Normally Closed (NC) auxiliary contact of the starter’s overload relay. When motor overload occurs, the overload relay (OLR) trips, opening the Normally Closed (NC) auxiliary contact, which interrupts the starter’s control circuit, de-energizing the electromagnetic coil of the contactor. This opens the contactor’s main contacts, interrupting current flow to the motor.
Direct-on-line starters are designed to control electric motors rated at 5 HP (Horsepower) and below because such starters do not have a voltage reduction mechanism to start a high-power motor safely.
B) Reversing Starters
Reversing starters incorporate two mechanically and electrically interlocked magnetic contactors – Forward and Reverse Contactors. These contactors provide reversed leads to the connected motor, allowing it to spin in either forward or reverse direction. The mechanical and electrical interlocks prevent the two contactors from closing simultaneously.
C) Reduced Voltage Starters
These starters are designed to control and limit the effects of high inrush currents during the startup of large- and medium-voltage motors undergoing full-line-voltage starts. They are available in electronic and electro-mechanical configurations. Typical reduced voltage motor starters include:
- Star-Delta/Wye-Delta Starters: These starters achieve voltage reduction during motor startup by physically reconfiguring the motor's windings. When the motor is starting, the windings get connected in a Star/Wye configuration. This results in a reduced voltage across each motor winding.
- Soft Starters: Soft starters use thyristors – solid-state semiconductor devices used in high voltage/current control applications – such as Silicon Controlled Rectifiers (SCRs) to limit the motor’s incoming voltage to a more manageable amount. This protects the starter-controlled motor from high starting currents that could potentially damage it.
D) Combination Starters
Combination starters are motor control devices that incorporate short circuit protection elements (such as circuit breakers or fuses) and disconnect switches together with the components of a motor starter (contactor and overload relay) into a single enclosure. These types of starters provide motor control functions, overload protection, and a disconnecting means for electric motors in diverse applications. They offer enhanced functionality, compactness, and reduced overall footprint in motor control systems.
Allen-Bradley IEC Combination starters include Reversing, Two-Speed, and Direct-On-Line operating modes. They are rotary-operated, and they also integrate 22.5 mm indication and command devices.
Functions of Motor Starters
The primary functions of motor starters can be summarized as:
- Motor Control: This function is executed by the contactor element of the starter. It involves controlling the ON and OFF switching of the motor’s power circuit. The switching is performed by the contactor’s main contacts (poles). In magnetic starters, the contactor’s electromagnetic coil gets energized or de-energized to close or open the power contacts. The coil has a rated control voltage, which can either be DC or AC voltage.
- Overload Protection: An overload condition occurs when an electric motor draws more current than its designed capacity. The main purpose of the starter’s overload relay is to detect an excessive current draw. On detecting an excessive current draw, the overload relay (OLR) trips, opening a Normally Closed (NC) auxiliary contact, which breaks the control circuit of the starter, de-energizing the contactor’s electromagnetic coil. This interrupts current flow to the motor, thereby preventing it from overheating or burning out.
- Short-Circuit Protection: Whenever a short-circuit fault occurs, over 100,000 Amperes of current can flow to equipment within the circuit. Such amounts of current can cause major equipment damage, given that the normal load current of even heavy-duty industrial equipment ranges up to a few thousand Amperes. For this reason, fuses or circuit breakers are included in motor starter units to provide short-circuit protection by safely disconnecting the motor from the main supply in the event of a short-circuit fault.
- Disconnecting and Breaking the Power Circuit: To prevent a motor from restarting unintentionally, for instance, after a loss of power or low voltage condition, the motor must be disconnected from the main power circuit when such conditions occur. Also, to safely carry out preventive maintenance on a motor or its starter, it should be possible to switch the motor off and isolate it from the power supply. A circuit breaker provides such functions as a disconnect switch in a Combination motor starter.
- Changing Motor Direction: There are motor starters with added functions to adjust the direction of rotation of the connected electric motor.
- Varying the Motor Speed: Some starters include additional features that enable them to vary the rotational speed (RPM speed) of an electric motor. Such starters include Four-Point DC Starters and Three-Point DC starters.
Selecting the Right 103 IEC Starter
Before we discuss the steps to follow when selecting a Bulletin 103 IEC starter, there are a few points one should keep in mind:
- All starters used to control electric motors share various power control functions. They are rated by Horsepower (Hp) or current in Amperes (A), including motor overload protection devices and an ON/OFF control circuit. They also include jogging and plugging functions that swiftly break or make a current.
- IEC-style starters are normally rated by their thermal current, maximum operating current, Horsepower (Hp) rating, and output power in kW.
- IEC-style motor starters are available as Open Frame or Enclosed starters, and they are usually sold as modular components comprising of a contactor, an overload relay, and an auxiliary contacts block. The modular components can easily snap on DIN rails of up to 75mm, or they can be panel mounted, allowing users to assemble the starter unit themselves. All you need is to select the right accessories for a complete assembly.
- Allen-Bradley IEC Open Frame starters include Direct-On-Line, Variable Speed, and Reversing operating modes. They feature a maximum operating current of up to 97 Amperes. While Allen-Bradley IEC Enclosed Combination starters include Reversing, Two-Speed, and Direct-On-Line operating modes. The Combination starters are available with maximum operating current and Horsepower ratings of up to 300 A (Amperes) and 250 HP, respectively.
Follow the steps below to select the proper Bulletin 103 IEC starter for your application.
- Review the Line Voltage and Contactor Size
Refer to the nameplate of the motor you intend to control using a Bulletin 103 IEC starter to verify its specified Full Load Amperage (FLA) at the line voltage you plan to provide. Confirm whether the line voltage to the motor is single-phase or three-phase. After doing so, select a Bulletin 103 IEC starter whose maximum operating current is higher than the Full Load Amperage of your motor at the line voltage you expect to use.
- Specify the Overload Relay Operating Range
It is important to select a Bulletin 103 IEC starter whose overload relay operating range will best match the amperage rating of your motor. To do so, you must select a Bulletin 103 IEC starter whose specified operating current range contains the Full Load Amperage of the motor you intend to control, as discussed in Step 1.
- Choose the AC coil Control Voltage
Allen-Bradley 103 IEC starters are magnetic motor starters that include a contactor with an electromagnetic coil, which is operated by a control circuit. As such, you will need to choose an appropriate control voltage that can energize the electromagnetic coil to create an appropriate electromagnetic field to close the contactor’s main contacts.
Note: If a Direct-On-line (DOL) 103 IEC starter will be used, the line power will be wired directly to the starter’s contactor and will thus be used as the control power. Hence, a separate control voltage is to be chosen when another type of starter is selected other than a Direct-On-line starter because, in such cases, the line voltage will not be the same as the control voltage.
Additionally, if the selected Bulletin 103 IEC starter requires activation from an external switch, additional terminals will be needed to accept the control voltage input from the external switch. The added terminals are referred to as “remote start terminals,” in such a starter configuration, the control voltage and line voltage are assumed to be the same. But another starter configuration is still possible, in which the remote start terminals are used. However, a different voltage is applied for control and line power; that configuration is referred to as “remote start terminals + separate control voltage.”
Therefore, based on the above criteria, you can select a Bulletin 103 IEC starter configuration that suits your preference.
- Select an Appropriate Enclosure
Bulletin 103 IEC Enclosed starters are offered in non-metallic and metallic enclosure types, which make them suitable for the most demanding indoor and outdoor industrial environments. Therefore, ensure that the enclosure of the 103 IEC starter you mean to select is designed to withstand the conditions of the intended working environment. Some of the enclosure types available with the Allen-Bradley 103 IEC Enclosed starters include:
- IP66 Plastic Enclosures, Type 4X/4/12K
- IP66 Metallic Enclosures, Type 12/4/3
Available 103 IEC Starters
Allen-Bradley 103 IEC Starters offers various motor control options to address light-duty and space-critical industrial-type applications. Available 103 IEC Starters include:
A) 103S-BSKF3-DC16C
The 103S-BSKF3-DC16C is a Direct-On-Line (DOL), Bulletin 103S IEC-rated 2-Component Combination motor starter featuring the following:
- IEC-rated contactor: size 100-C12
- Operating current range: 0.1 to 90 A
- Full voltage, non-reversing operating mode
- A Motor Protection Circuit Breaker (MPCB) with a current range of 10…16 A
- 230 Volts AC coil voltage rating, at 50/60 Hz (Hertz)
- Pre-configured to be mounted on the Bulletin 141A MCS (Modular Control System) Busbar Mounting System
- D-Frame circuit breaker frame size
- Open-type enclosure
- cULus Listed
B) 103S-GWD3-FC45C-F11
The 103S-GWD3-FC45C-F11 is a Direct-On-Line (DOL), Bulletin 103S IEC-compliant 2-component Combination motor starter with the following features:
- IEC-rated contactor: size 100-C43
- Operating current range: 0.1 to 90 A
- A Bulletin 140M Motor Protection Circuit Breaker (MPCB) with a current range of 32…45 A
- 110 Volts AC-rated control supply voltage (AC coil voltage) at 50 Hz
- 120 Volts AC-rated control supply voltage (AC coil voltage) at 60 Hz
- 141A panel mounting module
- F-Frame size
- Open-type enclosure
- cULus Listed
C) 103T-AWD2-RB25X-E1C
The 103T-AWD2-RB25X-E1C is a Direct-On-Line (DOL), Non-Reversing Bulletin 103T IEC-compliant 3-Component Combination starter featuring the following:
- IEC-rated contactor: size 100-C09
- Operating current range: 0.1 to 45 A
- E1 plus 3-phase Electronic Overload Relay
- Overload relay current range: 3.2...16 A
- A Short Circuit Protection Device (SCPD) consisting of a Motor Circuit Protector (MCP) or a 140M-D8N fuse holder
- Circuit breaker current range: 1.6 to 2.5 A
- 110 Volts AC coil voltage at 50 Hz
- 120 Volts AC coil voltage at 60 Hz
- 141A panel mounting module
- Open-type enclosure
- Circuit breaker frame size: High Break, 140M-C2N (C Frame)
- cULus Listed
D) 103T-AWD2-RB63X-E1D
The 103T-AWD2-RB63X-E1D is a Direct-On-Line (DOL), Non-Reversing Bulletin 103T IEC-rated 3-component Combination starter with the following features:
- IEC-rated contactor: size 100-C09
- Operating current range: 0.1 to 45 A
- An Electronic Overload Relay with a current range of 3.2 … 16 A
- A Short Circuit Protection Device (SCPD) consisting of a Motor Circuit Protector (MCP) or a 140M-D8N fuse holder
- Circuit breaker current range: 4 … 6.3 A
- 110 Volts AC coil voltage at 50 Hz
- 120 Volts AC coil voltage at 60 Hz
- 141A panel mounting module
- Open-type enclosure
- Circuit breaker frame size: High Break Plus, 140M-D8N (D Frame)
- cULus Listed
- Compliant with CE, UL, IEC, and CSA standards
E) 103C-09LB-CB16X-1M
The 103C-09LB-CB16X-1M is an Enclosed, Non-Reversing Bulletin 103C IEC-rated Combination starter. Its features are as follows:
- Direct-On-Line (DOL) starting
- Full voltage, non-reversing operating mode
- Rated control voltage: 480 Volts AC at 60 Hz or 440 Volts AC at 50 Hz
- IEC-rated contactor: size 100-C09
- Operating current range: 0.1 to 16 A
- Bulletin 140M Motor Protection Circuit Breakers that provide overload and short-circuit protection
- Circuit breaker thermal current range: 1 to 1.6 A
- Circuit breaker frame size: High Break, 140M-C2E (C-Frame)
- cULus Listed
- Impact-resistant, IP66 Molded Plastic Enclosure – Type 4X/4/12K
- Modifications: Start/Stop (Multi-Function Push Button)
- Well-suited for outdoor and indoor applications
