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Brand: STAMFORD
STAMFORD SX460 Automatic Voltage Regulator (AVR), Self-Excited
Description
A simple self-excited regulator for small and medium sets
The STAMFORD SX460 is a half-wave, phase-controlled thyristor automatic voltage regulator for brushless generators. Excitation power comes directly from the generator terminals, and the same input provides the sample voltage, so the AVR needs no PMG. It forms part of the excitation system on small and medium STAMFORD alternators, including the UC range.
Besides regulating voltage to +/-1.0 percent, the circuit provides under-speed and sensing-loss protection. Efficient semiconductors ensure positive build-up from residual levels, and the AVR is linked with the main stator windings and the exciter field winding in a closed loop.
Technical specifications
| Parameter | Specification |
|---|---|
| Part number (UC manual service parts) | E000-24602/1P |
| Input voltage | Jumper selectable: 95-132 V ac or 190-264 V ac, 1 phase, 50-60 Hz |
| Output | Max 90 V dc at 207 V ac input; 4 A dc continuous; 6 A intermittent for 10 s |
| Exciter field resistance | 15 ohms minimum |
| Regulation | +/-1.0% (with 4% engine governing) |
| Thermal drift | 0.05% per degree C (after 10 minutes) |
| System response | AVR 20 ms; field current to 90% 80 ms; machine volts to 97% 300 ms |
| External voltage adjustment | +/-10% with 1 k ohm, 1 W trimmer (mod status F onwards) |
| Under-frequency protection | Set point 95% Hz, jumper-selectable 50/60 Hz; slope 170% down to 30 Hz |
| Power dissipation | 10 W maximum |
| Build-up voltage | 4 V at AVR terminals |
| Vibration | 20-100 Hz 50 mm/s; 100 Hz-2 kHz 3.3 g |
| Operating temperature | -40 to +70 C; humidity 95% non-condensing; storage -55 to +80 C |
Controls and setting
Only three adjustments are provided: VOLTS, STABILITY and UFRO. The red LED shows when the under-frequency roll-off is operating. Terminals 1 and 2 carry a shorting link if no hand trimmer is fitted, and terminals 3 and 4 are linked only for special low-voltage applications. The knee point is factory set and can be changed between 50 and 60 Hz by a push-on link.
Replacement procedure
The datasheet sequence is: turn VOLTS fully anti-clockwise, set any remote trimmer to the middle, place STABILITY at mid position, connect a 0 to 300 V ac voltmeter line to neutral, run on no load at nominal frequency (50 to 53 Hz or 60 to 63 Hz) and then turn VOLTS clockwise to rated voltage. If instability appears, turn STABILITY slowly anti-clockwise until the voltage starts to hunt, then back it off slightly clockwise. Never exceed the rating plate voltage.
Matching the right AVR
The SX460 datasheet lists no droop CT input, so if the set must parallel with others confirm the arrangement on the alternator wiring diagram first. Choose according to the alternator wiring diagram and the code printed on the existing board, not by appearance.
Documents and quotation
Seven Star LLC supplies STAMFORD SX460 regulators on request. The datasheet is attached. Send the alternator model, serial number and old AVR code. See Diesel Generator Spare Parts for further generator parts or the Cummins C150D5 150 kVA diesel generator set for a complete set. Check the modification status before ordering a replacement; the external-trim range quoted applies to mod status F onwards. The design detail in the datasheet lists a low-pass filter that stops distorted waveforms disturbing the control circuit, and suppression components that guard against sub-cycle voltage spikes and reduce conducted noise at the generator terminals.
Typical system response in the datasheet is 20 ms for the AVR, 80 ms for field current to reach 90 percent and 300 ms for machine volts to reach 97 percent. Vibration is rated at 50 mm/s from 20 to 100 Hz and 3.3 g from 100 Hz to 2 kHz, and storage at -55 to +80 degrees C.
Datasheets & Documents
- Datasheet STAMFORD SX460 AVR specification, installation and adjustments TD_SX460 (EN) Download
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About brand
STAMFORD is the alternator brand of Cummins Generator Technologies, sold together with AvK as STAMFORD | AvK. Its history starts in 1904 with the Cutting Brothers' electrical engineering business in Stamford, England, later renamed Stamford Electrical. Newage Engineers bought Stamford Electrical in 1950, and Cummins took over Newage with Onan in 1986.
Seven Star LLC, an independent supplier in Muscat, sources these alternators and regulators for generator builders and plant owners in Oman and the GCC.
STAMFORD company profile
| Founded | 1904, Stamford, England, by the Cutting Brothers |
|---|---|
| Ownership | Cummins Inc., through Cummins Generator Technologies |
| Sister brand | AvK, founded in Frankfurt in 1919 as A. van Kaick |
| Range | Brushless AC alternators from 7.5 to 11,200 kVA |
| Product families | STAMFORD low and medium voltage alternators, AvK alternators for large and medium voltage sets, automatic voltage regulators such as MX341, MX321 and DM110, spare parts |
Milestones
- 1904: The Cutting Brothers start their business in Stamford.
- 1925: The company is renamed Stamford Electrical.
- 1950: Newage Engineers acquires Stamford Electrical.
- 1986: Cummins acquires Onan and with it Newage.
- 2006: The business is renamed Cummins Generator Technologies.
Alternators and AVRs listed here
The pages cover the S-Range alternators S0, S1, S4, S5, S6, S7K and S9LV, the UC22 and UC27 frames, and the AS480, MX321, MX341, MX342, SX460 and DM110 voltage regulators. Each page carries the ratings and specification from the maker brochure, datasheet or owner manual, including options as printed.
Where these alternators are used
The maker names data centres, marine, telecoms, standby and critical protection, combined heat and power, rail and prime power as typical applications, on diesel and gas engines. In the Gulf these are the same standby and prime-power sets used on camps, plants and pumping stations.
STAMFORD products we list
Ordering parts and alternators: what we need
For an alternator, send the model, serial number, winding number, kVA, voltage and frequency from the nameplate. For a regulator, send the code printed on the existing board and the alternator model, because the right replacement depends on the excitation system.
Facts checked against the STAMFORD | AvK heritage timeline and Grace's Guide, October 2026.
Related products
Frequently Asked Questions
What input does the SX460 accept?
95 to 132 V ac or 190 to 264 V ac, single phase, jumper selectable.
What output current does it give?
4 A dc continuous and 6 A intermittent for 10 seconds.
Does it need a PMG?
No. Excitation power is taken from the generator terminals.
What adjustments are on the board?
VOLTS, STABILITY and UFRO.
What is the regulation figure?
+/-1.0 percent with 4 percent engine governing.
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