432PSL6228 1-Phase - Marathon | 225 kW

Model. The 432PSL6228 1-Phase is a Marathon PSL 4-pole alternator. Marathon reads the model as frame 432 followed by the PSL family code and the winding number 6228. The frame sets the mechanical envelope and the family code sets whether the machine is wound for single-phase or three-phase service. It is wound for single-phase service at 60 Hz. Electrical rating. At 0.8 power factor lagging this machine is rated 225 kW, which is 281.2 kVA, delivered as single-phase at 240 V 60 Hz. At 240 V that is 1171.9 A through the line and the neutral. This is the band where motor starting, not steady-state kW, usually sizes the machine: a direct-on-line motor of roughly 30% of the alternator kVA will pull the terminal voltage down by about 15% at start, which is normally acceptable, and anything larger needs a soft starter or a bigger frame. The 1800 rpm figure is synchronous speed, so there is no slip and no speed-dependent voltage droop. Frame and core. The 432 frame carries the 6228 core. Frame size fixes the stator bore and the shaft centre height; the core length fixes how much active iron sits in that bore, and therefore how much output the machine can make at a given temperature rise. The exact finished weight and outline drawing depend on the winding and the coupling, so they are confirmed on the certified datasheet issued with the order. Outline dimensions in inches: A 21.46 in | B 15.00 | BA 10.00 | C 37.39 (C w/PMG 41.77) | D 22.64 | E 9.00 | 2F 11.00 | H 13.00 | P 24.97 | X 36.10 | Y 16.00 | Z 2.66. The cooling circuit is direct air cooled, IC01, and the frame is rolled steel frame, cast iron end brackets. Single-phase winding. This is a single-phase machine, so the winding is laid out to produce one sinusoid across the output terminals rather than a three-phase set. Single-phase alternators of this size are almost always fitted with a capacitor or a compounded excitation arrangement to hold the voltage steady as the load swings, because the pulsating armature reaction of a single-phase load pulls the terminal voltage around far more than a balanced three-phase load does. The practical consequence for the buyer is that single-phase kVA and three-phase kVA of the same frame are not interchangeable: the single-phase machine is derated for the same iron, and the wiring, the circuit breaker and the cable all have to be sized on the single-phase current, which is roughly 1.7 times the three-phase current for the same kVA at the same voltage. Four-pole build. A four-pole machine turns at 1500 rpm on 50 Hz and 1800 rpm on 60 Hz. That is the standard choice for generator sets from a few tens of kVA up to the low megawatt range, because the lower rotor speed gives a longer bearing life, a quieter fan, a higher subtransient reactance that is easier to coordinate with downstream protection, and a rotor that can carry a substantial damper cage for parallel operation. The trade is weight: a four-pole machine of a given kVA is roughly twice the mass of a two-pole one. Excitation and voltage regulation. The excitation system is self-excited brushless with SE350E AVR, regulated by SE350E standard / PM500 / DVR2400 with PMG, holding steady-state voltage to +/-1.0%. Marathon fits the SE350E as the standard regulator on the smaller frames, with the PM500 and the DVR2400 available where a PMG is specified. On the Mariner and harsh-duty builds the excitation stator is fully encapsulated and the rotating rectifier is a heavy-duty assembly with a 300% diode margin and sealed welded stud terminations, which is the difference between a machine that survives a damp boat hold and one that does not. Mechanical build. The frame is rolled steel frame, cast iron end brackets. Bearings are sealed for life ball bearings. Mounting is single bearing SAE flange or two bearing. Maximum overspeed is 2250 rpm, and the machine is rated for 1000 m. On the 280 to 430 frames the machine ships with twelve leads and a link board as standard, and the minimum inlet clearance is six inches. On the 570 frame and above the terminal box is mounted on top with the link board inside it, and a selenium surge suppressor is fitted as standard from the 360 frame up. Harsh-duty builds get multiple dip-and-bake cycles on the main stator. Where it fits. Factory and large commercial duty, plus marine auxiliary service. Loads include large induction motors, variable-speed drives, and rectifier front ends, all of which put harmonic current back into the alternator and make the winding pitch and the damper cage do real work. On a single-phase machine of 225 kW the practical constraint is usually the downstream protection and the cable, not the alternator itself. Core stack position. The 6228 core is stack position 25 of 25 in the PSL family, roughly 100% of the way along the family's lamination length range. It is the longest stack the PSL family is built with. Long-stack builds carry the rating in the frame with the lowest flux density of the family. The extra iron costs length and weight, and buys a cooler-running core, lower magnetising current, better part-load efficiency and more margin for site ambient above 40 C or for a non-standard voltage. Where it sits in the range. The PSL family is catalogued from 12 kW up to 175 kW, and this page covers the 225 kW / 281.2 kVA point. The step below it is the 431PSL6226 1-Phase at 175 kW, 218.8 kVA. It is the largest build in the family, so it is the one to quote when the load is fixed and there is no room for a second frame size. Reading the model code. A Marathon designation is read as the frame number, the winding family (PSL, CSL, CSA, RSL, FSL or FDL), and a four-digit winding code. Here that gives 432PSL6228 1-Phase for the model, 432 for the frame, 6228 for the core and single for the phase count, so the code on the nameplate and the code on this page match one for one. Quoting the full code rather than just the frame matters on this family, because the same frame number is built in several core lengths and the winding changes with the voltage. Frame position. The PSL range is built on 9 frame sizes — 281, 282, 283, 284, 285, 286, 287, 431, 432 — and the 432 frame is number 9 of them. No other frame in this range carries exactly this rating, so the 432 is the only build at 225 kW and there is no cross-frame decision to make. What the nameplate means once it is wired in. At 225 kW and 281.2 kVA this machine pushes 1172 A down each line on a 240 V single-phase supply. That current, not the kVA figure, is what the switchgear and the cable have to survive, so the outgoing breaker should be a 1600 A frame device set to trip above 1465 A, and the run from the alternator terminals to the first panel should be 400 mm2 copper per phase for a normal 25 to 30 m span. Longer runs, aluminium conductors or tray-installed cable all move that number up, and the volt drop at full load is what decides it in the end. On the mechanical side the prime mover has to deliver about 252 kW at the coupling. The usual 1.10 to 1.15 margin over the alternator rating covers the fan, the excitation loss and the governor droop, and it is the reason a 225 kW alternator is normally quoted against a 252 kW engine rather than a 225 kW one. Fuel burn follows the electrical load almost linearly in this range. At a realistic 0.29 L per kWh for a modern common-rail set, running this alternator at full rating takes roughly 65 L per hour; at 75 per cent load it drops to about 51 L per hour and at half load to about 36 L per hour, because the fixed losses stay put while the variable ones fall away. Quote the breaker frame, the cable size and the engine rating together with the alternator, because a set that is right on paper and undersized on the cable is the most common way a good alternator gets blamed for a bad installation. Supply. Supplied as a genuine Marathon unit — Regal Rexnord, built in United States. Marathon alternators are built by Regal Rexnord in the United States. Each alternator ships with the routine test certificate, the winding connection diagram, and the AVR commissioning sheet. Export packing is seaworthy plywood on a pallet sized to the frame, and the machine is strapped and shrink-wrapped inside it. Tell us the engine make and model, the coupling arrangement (single or two bearing), the voltage and frequency, and whether you need a PMG, and we will confirm the build before it leaves the works.