Allen BradleyNEMA Size 4 Full-Voltage Magnetic Motor Starter, 3-Pole, 135 A at 600 V AC Max, 40–100 HP 200–575 V Three-Phase, Open Type

Product Description

A NEMA Size 4 across-the-line magnetic motor starter from Allen-Bradley’s Bulletin 709 family: a three-pole magnetic contactor with a three-element overload relay, for full-voltage starting of three-phase squirrel-cage motors up to 100 HP.

Ratings, read from this unit’s own nameplate

The Allen-Bradley nameplate on this starter reads CATALOG NO. 709-EOD103, SIZE 4, Milwaukee, Wisconsin, U.S.A., with the rating table printed as:

MAX. RATINGS — 3PH, 3 POLE: 200 V → 40 HP; 230 V → 50 HP; 460–575 V → 100 HPMaximum continuous current: 135 A at 600 V AC maximumIn the Bulletin 709 catalogue scheme the letter after the bulletin number is the NEMA size, and E = Size 4. Series K.

The Bulletin 709 coil issue — know this before you install one:
Rockwell Automation obsoleted Bulletin 709 and replaced it with Bulletin 509 for a specific reason: on a 709, the moulded coil can overheat and swell, and a swollen coil case can jam the contactor mechanically in the ON position with no way to drop it out. The Bulletin 509 that replaced it uses a moulded coil with an internal thermal link — effectively a fuse — that opens the coil circuit before the case reaches swelling temperature. The large moulded coil is clearly visible in the centre of this starter in the photographs.

That does not make a 709 unusable, and it is often the only sensible repair for a legacy MCC bucket where a 509 will not fit the existing backpan and wireway. But it does mean three things: the coil is a wear item that should be inspected and ideally replaced rather than assumed good; the control circuit must be protected so the coil is not held energised at low voltage (a coil chattering at half voltage is how they cook); and where an unexpected failure-to-drop-out is a personnel hazard, the correct answer is to upgrade to a Bulletin 509 rather than to reuse a 709.

Configuration reality

This is an open-type starter on a heavy mounting bracket, as pictured. No enclosure, no disconnect and no branch-circuit protection are included, so a separate disconnecting means and short-circuit protective device are required. The photographs show three bolted line terminals with a factory copper jumper, three large load lugs, the moulded coil with its red control leads, three overload heater blocks and the mounting bracket. Overload trip current is set by the heater elements, which are sized to the motor’s actual full-load amps — the heaters fitted here were sized for the previous machine and must be verified or changed for yours.

Coil voltage — deliberately left blank

The nameplate on a Bulletin 709 carries the size and horsepower table but not the coil voltage; the coil is marked separately and its marking is not legible in the available photographs. Published reseller data for 709-EOD103 is contradictory — one source lists coil 74A86 at 110 V (50 Hz) / 120 V (60 Hz), another lists a 480 V coil — so coil voltage has been left blank rather than guessed. Read it off the coil before ordering; a mismatched coil is the single most common failure after installing a surplus starter. One reseller also describes 709-EOD103 as a reduced-voltage starter while the nameplate on this unit gives only full-voltage max ratings; the unit is being described here as what the nameplate supports.

Interchange and status

Bulletin 709 is obsolete; the direct successor is Bulletin 509, whose Size 4 series is the 509-E series (509-EOD and derivatives) with a Size 4 eutectic-alloy overload 40185-800-01 family part and Size 4 coils in the CE2xx range (CE236 for 115–120 V 60 Hz, CE273 for 460–480 V 60 Hz, CE278 for 575–600 V 60 Hz). Size 4 solid-state overload retrofits in the Bulletin 592 range include 592-A1KE (23–75 A), 592-A1LE (66–110 A), 592-A1ME (57–180 A), 592-B1ME and 592-C1ME (40–180 A). Related 709 part numbers include 709-BOD103 and 709-EOB16 — different sizes and coil options, not alternates. Also written 709EOD103, 709 EOD 103, 709-E0D103.

Source-data note: the previous title’s “40-100HP 200-575V AC” is confirmed correct against this unit’s nameplate and has been retained and itemised by voltage. The 135 A continuous rating, the 600 V AC maximum, the open-type construction, the coil obsolescence history and the Bulletin 509 successor path were absent from the record and have been added.