NEMA and IEC full-voltage non-reversing and reversing starters, reduced voltage autotransformer, part-winding, wye-delta, and solid-state soft starters. Combination starters, open and enclosed. Eaton, Square D, Allen-Bradley, ABB, Siemens, and legacy sourcing.
NEMA full-voltage starters are sized by NEMA designation rather than a specific ampere rating, with the size number mapping to a horsepower range at a given voltage. The sizing table to the right covers 3-phase 460V, which is the most common application. Single-phase and 208V ratings differ.
Full-voltage non-reversing (FVNR) starters are the most common type. Full-voltage reversing (FVR) starters use two interlocked contactors for forward and reverse operation. Multispeed starters are available for two-speed motor applications with separate winding or part-winding configurations.
Enclosure options cover NEMA 1 open, NEMA 1 enclosed, NEMA 3R, NEMA 4, NEMA 4X, and NEMA 12. The three main brands we source are Eaton Freedom (NEMA 00 through 9), Square D Class 8536 and 8606, and Allen-Bradley 500 series. All three cover the full NEMA size range with current production available.
| NEMA Size | Max HP @ 460V 3φ | Max FLA |
|---|---|---|
| 00 | 1.5 HP | 9A |
| 0 | 3 HP | 18A |
| 1 | 7.5 HP | 27A |
| 2 | 15 HP | 45A |
| 3 | 30 HP | 90A |
| 4 | 50 HP | 135A |
| 5 | 100 HP | 270A |
| 6 | 200 HP | 540A |
| 7 | 300 HP | 810A |
| 8 | 450 HP | 1215A |
| 9 | 800 HP | 2250A |
IEC starters are sized by current rating rather than horsepower and are generally more compact than NEMA equivalents at the same rating. They're common in OEM machine builds, imported equipment, and newer panel designs where physical space is a driver. Overloads are typically current-adjustable bimetallic or electronic types that mount directly to the contactor.
Eaton's XT product line for IEC contactors and overloads. The XTCE designates the contactor; XTOB is the overload relay. Current range covers low-ampere panel builds through larger motor applications. Direct replacement for older Moeller and Cutler-Hammer IEC products in many cases.
Schneider Electric's TeSys line is one of the most widely specified IEC contactor families globally. The D and K series cover most general-purpose motor starting applications. Overloads mount directly to the contactor and are adjustable within the rated range. Spare parts and accessories are broadly available.
The 3RT series is Siemens' current IEC contactor line. Common in facilities that run Siemens motor controls throughout. Sizes range from small pilot-duty contactors through large motor starters. 3RU overload relays mount directly and are bimetallic or electronic.
The 100-C is Rockwell's IEC-rated contactor line. Carries a higher price point than some competitors but is frequently specified in Rockwell-dominant facilities for parts consistency. Pairs with 193-series overload relays. Available in standard and reversing configurations.
A soft starter limits inrush current and controls motor acceleration by ramping the voltage up over an adjustable ramp time rather than applying full voltage immediately. This reduces mechanical stress on couplings, belt drives, and gearboxes, and cuts the inrush current spike that causes voltage sag on generators and utility feeders. At the end of the ramp, a bypass contactor typically closes and shunts the SCRs out of the circuit, eliminating the heat dissipation issue during run. The difference between a soft starter and a VFD is that a soft starter only controls the start and stop; it doesn't adjust speed during run.
Eaton's primary soft starter line. The S811 is the current generation; the S801 is the predecessor and still appears on replacement requests. Both carry adjustable ramp time, current limit settings, and built-in motor protection. The S811 integrates digital control with bypass contactor options. Commonly specified in Eaton switchgear and MCC applications.
Rockwell's SMC family. The SMC-3 is the entry-level, three-wire control unit with basic ramp adjustment. The SMC-50 is the higher-function version with current limiting, motor protection, and DeviceNet or EtherNet/IP communication options. Both are common in Rockwell-integrated facilities. Replacement units and spare parts for older SMC-2 and SMC Dialog Plus also come through.
ABB's soft starter range. The PSR is the compact, basic unit. The PST adds torque control and motor protection functions. The PSTB includes a built-in bypass contactor, simplifying the panel layout for applications where bypass is required. ABB soft starters appear frequently in pump and compressor applications where torque ramp is the primary concern.
Siemens offers a tiered soft starter family. The 3RW30 is the basic version with current limiting and ramp. The 3RW40 adds motor thermistor input and soft stop. The 3RW44 is the high-end unit with full motor protection and bypass. The 3RW55 is the newest generation with PROFINET/PROFIBUS communication. Frequently specified alongside Siemens 3RT contactors and WL switchgear.
Reduced voltage starters use electromechanical methods to limit inrush current during starting. They've largely been displaced by solid-state soft starters in new designs, but a significant installed base remains and replacement units come up on quotes regularly.
Autotransformer starters are the most common type in the older installed base. They apply a portion of line voltage through a starting autotransformer, then transition to full voltage after the motor reaches speed. Tap settings of 65% and 80% are standard; closed-transition and open-transition versions both exist. Open transition produces a brief interruption in motor current during the tap changeover; closed transition maintains continuity through the switch.
Part-winding starters are a simpler approach used for motors specifically wound to accept them. Wye-delta starters apply line voltage across the wye-connected windings at start, then switch to delta once near speed. All three types require motors designed or compatible with the starting method.
65% and 80% tap options. Open and closed transition. Most common legacy type for larger motors where inrush is the primary concern.
Two contactors energize separate windings in sequence. Requires a motor specifically designed for part-winding starting. Simpler mechanically than autotransformer types.
Motor starts in wye, transitions to delta near full speed. Reduces starting current to approximately 33% of full-voltage inrush. Requires 6-lead motor and appropriate control sequencing.
A combination starter packages a disconnect device (either a circuit breaker or a fusible disconnect switch) in the same enclosure as the motor starter and overload relay. This eliminates the need for a separate upstream disconnect and simplifies the panel layout for single-motor applications.
The circuit breaker version uses a motor circuit protector (MCP) or a standard MCCB. The fusible version uses a fused disconnect switch. Both can be enclosed in a variety of NEMA ratings. Combination starters appear frequently in standalone pump panels, compressor control panels, and equipment that requires a dedicated locally-mounted disconnect point.
Combination starters are available in NEMA and IEC configurations. For replacement units, the catalog number from the existing nameplate is the most reliable way to get the right unit, since the breaker/fuse sizing and contactor rating need to match the original design intent.
Legacy motor starters come up frequently on replacement requests. The nameplate on the existing unit usually has enough information to identify what's needed. Condition is disclosed clearly with every quote.
Older Eaton and Cutler-Hammer NEMA starters (pre-Freedom series), Furnas Electric starters (now Siemens), and GE CR306 series starters are sourced through surplus channels as available. These are not guaranteed-stock items. If you're working on a direct replacement and the existing unit is still operational, it's worth having the replacement in hand before pulling the original.
For most motor starters, the catalog number from the existing unit or a specification sheet is the cleanest path to a quote. If neither is available, the parameters below cover what we need to determine the right unit.
For soft starters, include whether a bypass contactor is required, whether motor protection functions need to be built into the soft starter or handled separately, and any communication requirements.
Use the quote form and include the motor nameplate data if you have it. For soft starters, note whether bypass and communication are required.
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