Product Overview

The Allen-Bradley 150-C19NBD SMC-3 Smart Motor Controller is a solid-state motor starting and stopping device developed by Rockwell Automation for three-phase AC motor applications. As part of the Bulletin 150 SMC-3 product family, it provides controlled motor acceleration, soft stopping, and integrated motor overload protection in a compact open-type design.

Unlike a variable frequency drive, which continuously adjusts motor speed by changing output frequency, the SMC-3 is primarily designed to manage motor starting and stopping. It gradually increases the voltage applied to the motor during startup, helping reduce the electrical and mechanical stress associated with direct-on-line starting. Once the motor reaches its operating condition, the integrated bypass function helps reduce power losses during normal operation.

The 150-C19NBD has a rated current of 19 A and is designed for three-phase power circuits up to 480 V AC. Its control voltage range is 100–240 V AC, making it suitable for industrial control panels using compatible AC control supplies.

The controller offers selectable current-limit settings, adjustable starting times, selectable initial torque, and soft-stop functions. It also provides integrated motor overload protection and diagnostic relay contacts for reporting overload or fault conditions.

With its compact dimensions of 139.7 × 44.8 × 110 mm and a weight of approximately 0.86 kg, the 150-C19NBD can be incorporated into appropriately designed motor-control panels. It is commonly considered for pumps, fans, conveyors, compressors, and other industrial machines where controlled motor starting is required.

Technical Specifications

Note: Motor power capability varies with supply voltage, motor connection, starting duty, and application conditions. Always use the manufacturer’s selection tables and motor nameplate data when sizing the controller.

Function and Working Principle

The 150-C19NBD uses solid-state switching technology to control the voltage applied to a motor during startup and stopping. This provides a more controlled transition between stationary and running conditions than conventional direct-on-line starting.

1. Soft Starting

When a motor starts directly across the supply, it can draw a high inrush current and produce substantial starting torque. These effects may cause voltage dips, mechanical shock, and stress on connected equipment.

The SMC-3 gradually increases the motor voltage according to its configured starting parameters. This allows the motor to accelerate more smoothly and can reduce the mechanical impact on shafts, couplings, belts, and driven machinery.

2. Adjustable Starting Time

The controller provides selectable starting times of 2, 5, 10, 15, 20, 25, or 30 seconds.

The appropriate setting depends on motor characteristics, load inertia, and the required machine cycle. A longer starting time may provide a smoother acceleration profile, but it must remain within the motor’s thermal limits and the controller’s permitted starting duty.

3. Selectable Current Limit

The 150-C19NBD offers selectable current-limit settings of 150%, 250%, 350%, and 450% of the motor’s full-load current.

This function allows engineers to configure the starting current according to the electrical supply and mechanical load requirements. The selected current limit must provide sufficient torque to accelerate the connected load.

A setting that is too low may prevent the motor from accelerating properly, while a higher setting may increase electrical and mechanical stress.

4. Initial Torque Adjustment

The controller provides selectable initial torque settings of 15%, 25%, 35%, and 65% of locked-rotor torque.

This feature helps match the initial motor response to the characteristics of the driven machine. For example, a lightly loaded conveyor may require a different starting torque from a pump or compressor with a more demanding starting condition.

5. Integrated Bypass

After the motor reaches its operating condition, the internal bypass function provides a path that reduces the need for continuous solid-state switching during normal operation.

This helps reduce heat generated by the power electronics and supports efficient operation within the controller’s rated conditions.

6. Soft Stop

The soft-stop function gradually reduces motor voltage during stopping when the application is configured and wired for this feature.

This can help reduce abrupt mechanical deceleration in equipment such as pumps and conveyors. The actual stopping behavior depends on the load, mechanical inertia, and configured stop parameters.

7. Motor Overload Protection

The controller includes integrated motor overload protection. Selectable trip classes allow the protection response to be matched to the motor’s starting and operating characteristics.

Correct motor full-load current settings are essential. The soft starter should not be treated as a substitute for every form of short-circuit protection or system-level safety protection.

Role in Industrial Control Systems

The 150-C19NBD is typically installed in a motor starter circuit and operates alongside circuit protection, contactors where required, PLCs, control relays, and operator interfaces.

PLC Integration

A programmable logic controller can issue start and stop commands through the appropriate control circuit. It can also monitor the controller’s auxiliary status and fault contacts.

The SMC-3 provides control inputs and relay contacts that can be incorporated into a suitable PLC-based motor-control architecture. Wiring must follow the manufacturer’s terminal diagrams and the required control logic.

Motor Protection Coordination

The controller’s overload protection can form part of the motor protection strategy. Upstream fuses or circuit breakers must still be selected according to the manufacturer’s short-circuit protection coordination tables and applicable electrical standards.

Proper coordination is important because motor overload protection and short-circuit protection perform different functions.

HMI and Operator Control

An HMI can provide operators with start and stop controls, alarm indications, and equipment status when integrated through a PLC or suitable control circuit.

This makes it possible to incorporate the SMC-3 into centralized machine-control systems without requiring the controller itself to provide a full operator display.

Industrial Equipment Coordination

In a production line, the SMC-3 can be used to start motors in a controlled sequence. PLC logic can coordinate the motor with upstream and downstream machinery, reducing unexpected equipment movement during startup.

Industrial Applications

The Allen-Bradley 150-C19NBD is suitable for three-phase motor applications that require controlled starting and stopping rather than continuous variable-speed regulation.

1. Pumping Systems

Pumps may experience pressure changes and mechanical stress during startup and stopping. Soft-start functionality can help reduce abrupt acceleration and may improve the transition between operating states.

In suitable pumping applications, soft stopping can also help reduce sudden changes in flow. The actual result depends on the pump design, pipework, fluid characteristics, and system configuration.

2. Conveyor Systems

Conveyor motors often drive belts, rollers, and material-handling mechanisms. Direct-on-line starting can create sudden mechanical movement and place stress on belts, couplings, and transported products.

The SMC-3 can provide controlled acceleration, helping the conveyor reach operating speed more smoothly.

3. Industrial Fans and Blowers

Fans and blowers may require controlled startup to reduce mechanical shock and electrical inrush current.

The 150-C19NBD can be used with compatible three-phase motors where the required starting torque and current fall within its ratings.

4. Air Compressors

Some industrial compressor installations require controlled motor starting to reduce the impact of starting current on the electrical supply.

Before applying the SMC-3, engineers should confirm the compressor’s unloading arrangement, starting torque, motor current, and permitted starting frequency.

5. Material Handling Equipment

Lifting auxiliaries, feeders, and other material-handling machines may use soft starters to reduce sudden mechanical loading during motor startup.

The SMC-3 can be considered for compatible single-direction motor applications. Applications requiring precise speed control, reversing, or specialized braking need additional equipment and a different control strategy.

6. General Manufacturing Machinery

The controller may be used in industrial machines where smooth motor starting, overload protection, and straightforward PLC coordination are required.

Its 19 A current rating should be checked against the actual motor full-load current and starting duty before selection.

Installation and System Integration

Correct installation is necessary to ensure reliable operation and appropriate motor protection.

1. Verify Electrical Ratings

Confirm that the motor and supply are compatible with the controller’s three-phase voltage and 19 A current rating.

Check the motor nameplate, full-load current, starting torque, operating duty, and supply frequency. The controller should be selected using the manufacturer’s motor selection information rather than motor power alone.

2. Install in a Suitable Enclosure

The 150-C19NBD has an open-type construction and an IP2X protection rating. It should be installed in a suitable electrical enclosure that provides protection against the surrounding environment.

The enclosure must allow adequate heat dissipation and provide access for wiring and maintenance. Consider ambient temperature, ventilation, and the heat produced by other components inside the panel.

3. Connect the Power Circuit

Connect the three-phase supply and motor conductors according to the manufacturer’s wiring instructions.

Use conductors with appropriate current and temperature ratings. Confirm terminal tightening torque and ensure that the grounding arrangement meets applicable electrical requirements.

4. Connect the Control Circuit

The 150-C19NBD uses a 100–240 V AC control supply. Verify the actual control voltage before connecting the control terminals.

Start and stop commands, interlocks, and auxiliary relay contacts should be wired according to the application design. Avoid assuming that control terminals from another SMC-3 model have identical functions without checking the documentation.

5. Configure Starting Parameters

Select the initial torque, starting time, current limit, and overload trip class according to the motor and load.

A suitable configuration should allow the motor to accelerate reliably without exceeding the permitted starting current or thermal limits.

6. Test the Motor and Protection Functions

After wiring and parameter checks, conduct a controlled startup test.

Verify motor rotation, acceleration time, current behavior, stopping response, overload settings, and fault indication. Confirm that PLC interlocks and emergency-stop circuits operate according to the machine’s safety design.

Compatible System Components

The 150-C19NBD is commonly installed with other motor-control and automation components.

The components listed are examples of a typical installation. They are not necessarily included with the 150-C19NBD.

Alternative Models and Replacement Considerations

When replacing the 150-C19NBD, the alternative should be selected according to current rating, voltage, control voltage, enclosure type, and motor starting requirements.

A replacement should not be selected solely because it belongs to the same product family. Verify the complete catalog number, motor ratings, control voltage, terminal arrangement, protection settings, and physical dimensions.

Key Advantages

Controlled Motor Starting

The SMC-3 provides adjustable starting parameters that help reduce the mechanical and electrical impact of direct-on-line motor starting.

Integrated Overload Protection

Built-in motor overload protection helps protect compatible motors when the controller is configured according to motor nameplate data.

Adjustable Starting Characteristics

Selectable current limits, initial torque settings, and starting times allow the controller to be adapted to different load conditions.

Internal Bypass

The integrated bypass helps reduce continuous power-electronic losses after the motor has started.

Soft-Stop Capability

The soft-stop function can help reduce abrupt motor stopping in suitable applications.

Compact Installation

Its 139.7 × 44.8 × 110 mm dimensions and 0.86 kg weight make it suitable for compact motor-control panel installations.

PLC Compatibility

The controller’s control inputs and auxiliary contacts can be incorporated into PLC-based automation systems through suitable wiring and control logic.

Technical FAQs

1. What is the Allen-Bradley 150-C19NBD?

The 150-C19NBD is an SMC-3 Smart Motor Controller from Rockwell Automation. It is a solid-state soft starter designed to control the starting and stopping of compatible three-phase AC motors.

2. What is the rated current of the 150-C19NBD?

Its rated current is 19 A. The motor’s actual full-load current and starting requirements must be checked before selecting the controller.

3. What voltage does this controller support?

The power circuit is designed for three-phase AC applications up to 480 V. Its control voltage range is 100–240 V AC.

4. Is the 150-C19NBD a variable frequency drive?

No. It is a soft starter, not a variable frequency drive. It controls motor acceleration and stopping but does not provide continuous variable-speed operation by changing the output frequency.

5. Does it have integrated motor overload protection?

Yes. The SMC-3 includes integrated motor overload protection with selectable trip classes. Correct configuration is necessary to match the motor’s rated current and operating conditions.

6. What starting-time settings are available?

The selectable starting times are 2, 5, 10, 15, 20, 25, and 30 seconds. The appropriate setting depends on motor characteristics and load requirements.

7. Does the controller support soft stopping?

Yes. It provides selectable soft-stop functionality. The stop behavior depends on the application wiring and configured parameters.

8. Can the 150-C19NBD work with a PLC?

Yes. It can be integrated into PLC-based motor-control systems through its control inputs and auxiliary status contacts. The wiring and PLC logic must follow the controller’s documentation.

9. What is the difference between 150-C19NBD and 150-C19NBR?

Both belong to the SMC-3 family and have a 19 A current rating, but their control voltage configurations differ. The 150-C19NBD uses 100–240 V AC control, while the 150-C19NBR uses 24 V AC/DC control. They should not be treated as direct substitutes without checking the control circuit.

10. What should be checked before replacing this controller?

Verify the complete catalog number, rated current, supply voltage, control voltage, motor full-load current, overload settings, terminal wiring, and enclosure requirements. Also confirm the condition and compatibility of any associated protective devices.

Procurement and Maintenance Recommendations

When purchasing the Allen-Bradley 150-C19NBD, confirm the complete catalog number and inspect the controller’s nameplate. Check its 19 A rating, three-phase power requirements, 100–240 V AC control voltage, and open-type construction.

For used or refurbished equipment, inspect the power terminals, control terminals, housing, and visible electronic components. Ask for available testing information and confirm whether the controller has been inspected for abnormal heating or electrical damage.

During maintenance, check terminal tightness, panel ventilation, wiring insulation, grounding, and the condition of associated protective devices. Review overload settings whenever the connected motor is replaced or the application changes.

Keep the controller’s parameter settings and wiring information documented. This helps reduce commissioning time when a replacement is required.

Conclusion

The Allen-Bradley 150-C19NBD SMC-3 Smart Motor Controller is a compact 19 A solid-state soft starter designed for three-phase AC motor applications. With 100–240 V AC control voltage, integrated motor overload protection, adjustable starting parameters, internal bypass, and soft-stop capability, it provides controlled motor starting and stopping for a range of industrial machines.

Its 139.7 × 44.8 × 110 mm dimensions and 0.86 kg weight make it suitable for appropriately designed control panels. For installation and replacement projects, engineers should verify the motor’s electrical requirements, control voltage, protective-device coordination, and complete controller configuration before commissioning.