STAMFORD and AvK Alternator
Spare Parts Supplier
STAMFORD and AvK are the two alternator brands of Cummins Generator Technologies, and STAMFORD machines are offered for marine use. Plates and regulators made before the Cummins name may read Newage instead. Each request starts from the alternator plate and the regulator type, and every line goes out as a genuine part or a checked alternative, confirmed before pricing.
STAMFORD, Newage and AvK equipment on board
First a STAMFORD frame from a marine pairing, then the four STAMFORD regulator types grouped by their power supply, then the AvK alternators and their regulator, and last the older plate names and the rectifier parts. A Leroy-Somer plate belongs on the Leroy-Somer page.
HCM634
Cummins pairs the HCM634 with one of its marine engines in its own alternator matching, and a machine with an HCM634J2 plate has been offered, with its own photographs, in the used-equipment trade. The letters and figures after 634 are part of the type. The parts list belongs to one machine, so the full plate line travels with the serial number.
MX341 · MX321
Both draw their power from a permanent magnet generator (PMG) rather than from the main winding, yet they are separate regulators with separate wiring. On a machine with a PMG, the type printed on the fitted label decides which of the two is priced.
SX440 · AS440
Both are self-excited: they are supplied from the alternator's main winding, with no PMG in the circuit. Traders sell the SX440 for machines with Newage Stamford plates, and the AS440 appears in the maker's own AVR list. Going from a self-excited type to a PMG-powered one, or back, changes the excitation wiring and is planned from the documents.
DIG 110 · DIG 120 · DIG 130
DIG is the AvK alternator range of Cummins Generator Technologies. Used DIG 110, DIG 120 and DIG 130 machines are listed by resellers with their own photographs and condition notes. The letter and figure that follow the frame number belong to the type, so the request carries the whole plate line and the serial number.
COSIMAT N+
A regulator the maker lists for AvK alternators and that alternator-parts traders still sell. It is priced from the type on the unit fitted and the alternator serial number. Where the maker names a follow-up type, that type and any wiring change are written into the quote.
Newage · Newage Stamford
Older STAMFORD alternators and regulators carry the Newage or Newage Stamford name, from before the business became Cummins Generator Technologies. Such a plate gives the same three facts as a STAMFORD one, type, serial number and frame, while the regulator type is read from its own label.
Diode kits and surge suppressor
STAMFORD alternators are brushless, so the diodes that feed the rotor turn with the shaft, protected by a surge suppressor. Rectifier kits for STAMFORD frames come from the maker and from alternator-parts traders. Each kit is matched by the reference on the part and a photo of the rectifier in place.
How a STAMFORD or AvK alternator ends up in a request
Such a request may start with excitation: the set will not build voltage, or the voltage wanders once load is applied. What gets measured depends on the machine. With a PMG, the PMG output to the regulator is checked along with the regulator; on a self-excited machine, the feed from the main winding. Anything found in the rotating rectifier changes the part list, so the electrician's findings travel with the request.
After a short circuit or a closing out of phase, each diode and the surge suppressor are tested, and the request states whether loose parts or a full rectifier kit is wanted. A machine that has stood in a damp space is megger tested before it runs; the insulation resistance calculator turns the readings into PI and DAR. A bearing reported for noise, heat or vibration is ordered by the marking on the bearing or its parts list item. On a machine whose bearings take grease, the bearing grease quantity calculator works out the grams to add at each relubrication from D and B, and the number of strokes for a gun weighed on board.
STAMFORD and AvK parts we can quote
Nothing is priced from a description alone: each item below is identified from a plate, a label, the part itself or the alternator parts list.
- MX341, MX321, SX440, AS440 and COSIMAT N+ regulators, priced against the type on the fitted unit
- Rectifier kits and loose diodes for the rotating rectifier, identified by the part reference
- The surge suppressor (varistor) that protects the rectifier
- PMG components on machines that carry one
- Droop current transformers used for parallel running, identified from their own label
- Bearings, identified by the marking on the bearing itself
- Anti-condensation heaters and terminal box parts, if the machine has them
- Inlet air filters, on machines built with them
What to send for a STAMFORD or AvK alternator
A STAMFORD frame can be built with or without a PMG and leave the works with a different regulator. The list below shows which build is on board before anything is priced.
- The alternator nameplate photographed in full, whether it reads STAMFORD, Newage or AvK
- The regulator: its type label and a picture showing it in the terminal box
- Its wiring, photographed with all leads still connected
- PMG or self-excited, as stated in the alternator documents or wiring diagram
- For a rectifier fault: the reference on the diode or kit and a picture of the rectifier on the shaft
- Poles, frequency and speed from the plate; the motor speed calculator checks that they agree
- For a transformer fed by the set: its vector group, read with the vector group reader
Supply route review for STAMFORD and AvK alternators
Every line is weighed as a genuine part or a checked alternative, and the choice is confirmed before a price is given. Regulators and rectifier assemblies are identified by type.
Two facts per regulator
A STAMFORD regulator is identified by the type printed on the fitted unit and by whether the alternator powers it from a PMG or from its own winding. A request for 'a Stamford AVR' carries neither, and the four STAMFORD types differ in wiring and sensing, so it cannot be priced as it stands.
Copies of MX-range regulators
In a 2021 notice Cummins Generator Technologies warned that copy AVRs were being sold under its MX-range identifiers, and the trade press reported the warning. Boards described as compatible with STAMFORD types are on open sale as well. The label photo and the supplier's evidence for the actual unit are compared before quoting.
Where an alternative is acceptable
Regulators and rectifier parts go out as genuine parts identified by type. Bearings, air filters and similar generic items may be offered as a checked alternative if the buyer agrees, after their marking has been compared and the supply route settled.
Same group as the engine, separate plate
Cummins Generator Technologies belongs to the same group as Cummins engines. The alternator still has its own plate and parts list: engine parts are read on the Cummins engine page, alternator and regulator parts here.
STAMFORD and AvK alternators — questions buyers ask
Our plate says Newage, not STAMFORD. Is this the right page?
Yes. Newage built STAMFORD alternators before the business became Cummins Generator Technologies, and a Newage plate is read like any STAMFORD plate. Send it as it reads, together with the regulator label.
Is 'a Stamford AVR' enough to get a quote?
No. SX440, AS440, MX321 and MX341 are four different regulators: two take their power from a PMG, two are self-excited, and their wiring differs. We need the type on the fitted label, a photo of its terminals and the alternator plate.
Can an AS440 replace the MX341 on our alternator?
Not as a straight swap. The MX341 is powered by the PMG and the AS440 by the alternator's own winding, so the change touches the excitation wiring. Any change of type is worked out from the alternator documents and stated in the quote.
An MX341 is offered online by a seller we do not know. Is it the genuine part?
Not necessarily. The maker has warned about copies sold under its MX-range names, and boards described as compatible with STAMFORD types are openly on sale. The label and the supplier's evidence for that unit are checked before it is quoted.
Do you quote parts for AvK alternators too?
Yes. Send the AvK plate with the DIG or other type line and the serial number, and the label of the regulator fitted, COSIMAT N+ or another type.
Is Vessel Core connected to STAMFORD | AvK?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with STAMFORD | AvK, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the STAMFORD or AvK plate and the AVR label
Frame, type, serial number and regulator type are enough to read the request against the machine on board. Missing a piece? Send what you have and we will ask for the rest.
