Description
Allen-Bradley 509-FOD-XXX | NEMA Size 5 Motor Starter (270A)
Dynamic Product Introduction
Starting and protecting heavy multi-horsepower motors across mining, municipal pumping, or steel processing facilities requires uncompromising contact arc suppression and rugged mechanical interlocking. The Allen-Bradley 509-FOD-XXX is a NEMA Size 5 non-reversing full-voltage motor starter engineered to govern high-demand 3-phase loads up to 270 amperes.
Deciphering the catalog code reveals its exact hardware footprint: 509 designates the Bulletin 509 NEMA starter line, F indicates the physical NEMA Size 5 frame size, O represents an open-type construction (no enclosure) for panel integration, D specifies a 110V 50Hz / 120V 60Hz operating coil, and the XXX suffix designates a base unit shipped without factory-installed overload heater elements or auxiliary options. Installing a bench-audited 509-FOD-XXX restores immediate, high-torque switching performance while protecting downstream machinery against thermal lockups.
509-FOD-XXX
Key Technical Specifications
| Parameter | Specification Detail |
| Catalog Number | 509-FOD-XXX |
| OEM Manufacturer | Allen-Bradley / Rockwell Automation |
| NEMA Frame Size | Size 5 (up to 200 HP @ 460/575V) |
| Continuous Current Rating | 270 Amperes |
| Power Pole Configuration | 3-Pole (Top-Wired) |
| Coil Voltage | 110 VAC @ 50 Hz / 120 VAC @ 60 Hz (Code “D”) |
| Maximum Voltage | 600 VAC Max |
| Enclosure Type | Open-Type (“O” Code for panel mounting) |
| Compatible Overload Relays | Bulletin 592 Eutectic Alloy or Solid-State Overload Relays (e.g., 592-A1NF / 592-B1NF) |
| Auxiliary Contacts | 1 N.O. Hold-in interlock contact standard |
Global Sourcing & Live-Test SOP (Transparency Core)
High-current NEMA starters handle thousands of operating cycles under high inductive load. To guarantee immediate field reliability, every 509-FOD-XXX starter undergoes rigorous physical and electrical bench verification:
Inbound & Mechanical Verification
- Inspection of main silver-cadmium oxide power contacts for pitting, erosion, or uneven contact alignment.
- Checking spring tension across all three power pole armatures to confirm balanced contact pressure during coil pickup.
- Verification of coil housing, arc chutes, and terminal bus bars for thermal cracking or flashover carbon tracking.
Coil & Electrical Diagnostics
- Coil winding resistance and insulation integrity are tested to verify zero turn-to-turn shorting under load.
- Pickup (pull-in) and drop-out voltage levels are measured across the 120 VAC control terminals to ensure rapid, chatter-free actuation.
Thermal & Load Simulation
- High-current continuity testing across all main power contacts confirms milliohm-level contact resistance.
- Dielectric insulation testing (Hi-Pot) up to 2,500 V testing ensures complete isolation between phase poles and ground frame.
Final Prep
- Main terminal bus surfaces are polished and treated with conductive anti-oxidation grease.
- Securely wrapped and packaged with custom shock-absorbing foam to protect heavy iron-core armatures during transport.
The Field Engineer’s Pitfall Guide
❗ Overlooking the “XXX” Suffix Configuration: The XXX suffix in Allen-Bradley nomenclature signifies that the starter is shipped as a base unit without pre-configured overload heater elements or custom auxiliary contact blocks. Before dropping a 509-FOD-XXX into service, you must transfer your existing Bulletin 592 overload relay or specify match-calibrated heater elements tailored to your motor’s Full Load Amperage (FLA).
❗ Connecting Direct 24 VDC Control Logic to a 120 VAC Coil:The D code in 509-FOD-XXX indicates a 110/120 VAC operating coil. Driving this coil directly from a 24 VDC PLC output card without an intermediate interposing relay will prevent the heavy Size 5 contactor from picking up, or damage the PLC output.
❗ Neglecting Arc Chute Maintenance and Clearance: Size 5 starters interrupt heavy arc currents during motor shutdown. Mounting an open-type starter (O code) without maintaining proper vertical clearance above the arc chutes can result in phase-to-phase flashover or cabinet lid degradation during high-load emergency stops.
Intent-Driven FAQ
What does the catalog code breakdown mean for 509-FOD-XXX?
- 509: Bulletin 509 NEMA non-reversing motor starter platform
- F: NEMA Size 5 frame size (270 A continuous)
- O: Open-type construction (no enclosure included)
- D: 110 VAC 50Hz / 120 VAC 60Hz control coil
- XXX: Standard factory configuration without pre-selected overload options
Can I upgrade the overload relay on this starter to a solid-state unit?
Yes. The 509-FOD-XXX can be fitted with traditional Bulletin 592 eutectic alloy overload relays or retrofitted with modern Allen-Bradley E100/E300 electronic solid-state overload relays for enhanced phase-loss and ground-fault protection.
How do I convert this 120 VAC coil starter to operate on 240 V or 480 V control power?
You can either replace the internal “D” code coil assembly with an alternative voltage coil (such as a “B” for 240 V or “C” for 480 V) or install a standard 480V-to-120V control power transformer (CPT) inside the enclosure.
What is the maximum horsepower motor this starter can control?
At 460V or 575V 3-phase AC, a NEMA Size 5 starter (270 A) is rated to control motors up to 200 HP. At 230V 3-phase, it is rated up to 100 HP.
What warranty coverage is provided with surplus or refurbished units?
Every Allen-Bradley 509-FOD-XXX starter passing through our bench qualification protocol includes a full 1-year replacement warranty covering coil actuation, power contact conductivity, and structural frame integrity.
