STAMFORD MX321/MX322/MX341/MX342 — analog voltage regulators with PMG supply
Country: United Kingdom · Model: MX321/MX322/MX341/MX342
The analog voltage regulators MX321, MX322, MX341 and MX342 for brushless generators with excitation from a permanent-magnet sub-exciter. The output is up to 120 V DC, and the accuracy is ±0.5 % for the MX321 and ±1 % for the MX341 and MX342. They suit generators of 0.1–3.6 MVA.
- Sensing
- MX321/MX322 — 3-phase, 190–264 V; MX341/MX342 — 2-phase (1 phase, 2 wires), 190–264 V
- PMG supply
- 140/170–220 V, 3 phases, 3 A/phase, 100–120 Hz
- Output
- up to 120 V DC; continuous 3.7 A (MX321) / 2.7 A (MX341, MX342); 6 A for 10 s
- Load resistance
- not less than 15 Ω
Technical specifications
| Sensing | MX321/MX322 — 3-phase, 190–264 V; MX341/MX342 — 2-phase (1 phase, 2 wires), 190–264 V |
|---|---|
| PMG supply | 140/170–220 V, 3 phases, 3 A/phase, 100–120 Hz |
| Output | up to 120 V DC; continuous 3.7 A (MX321) / 2.7 A (MX341, MX342); 6 A for 10 s |
| Load resistance | not less than 15 Ω |
| Accuracy | ±0.5 % (MX321), ±1 % (MX341/MX342) |
| Thermal drift | 0.02–0.03 %/°C |
| Response time | 10 ms AVR; 97 % of voltage in 300 ms |
| External trim | ±10 % |
| Frequency protection | setpoint 95 % (MX341); MX342 — linear V/Hz characteristic down to 18 Hz |
| Power dissipation | not more than 12 W |
Specifications are taken from the manufacturer’s technical documentation. Updated .
Description
Supplying the power circuit from a three-phase PMG separates the control circuit from non-linear loads and makes it possible to maintain the steady-state short-circuit current. The MX321 senses voltage in three phases (190–264 V, 2 or 3 phases, 50–60 Hz), is supplied from a PMG of 170–220 V, 3 A per phase, 100–120 Hz, and delivers 3.7 A continuously and 6 A for 10 s. Thermal drift is 0.02 %/°C, soft start is 0.4–4 s, response is 10 ms, field current reaches 90 % in 80 ms, voltage reaches 97 % in 300 ms, and trim is ±10 %. The MX322 has three-phase sensing and is standard for the S7 K-core and S7 Water-Cooled. The MX341 senses in two phases (190–264 V, 1 phase, 2 wires), is supplied from 140–220 V, delivers 2.7 A, has a thermal drift of 0.03 %/°C and a soft start of 3 s, and dissipates up to 12 W. The MX342 is close to the MX341 and adds a linear V/Hz characteristic down to 18 Hz and a ±5 V input.
How to choose
The regulator is selected by machine model. The MX321 is standard on the S6 and HC6, the MX322 on the S7 K-core and S7 Water-Cooled, and the MX341 on the S7 and P7, while the MX342 is fitted optionally across the whole STAMFORD range, in particular the S-Range. In new machines they are gradually being replaced by the digital VITA 05 with compatible mounting points.
Request a price and lead time
STAMFORD MX321/MX322/MX341/MX342 — analog voltage regulators with PMG supply. We reply within one business day.
Or email office@usk.ua or call +38 (044) 339-50-20.
FAQ
How does the MX321 differ from the MX341?
The MX321 senses in three phases and holds ±0.5 %, and is supplied from a PMG of 170–220 V. The MX341 senses in two phases, holds ±1 % and is supplied from 140–220 V.
What is the output current of the MX321 and MX341?
The MX321 delivers up to 120 V DC at 3.7 A continuously and 6 A for 10 s. The MX341 delivers 2.7 A continuously.
What is the linear V/Hz characteristic of the MX342 needed for?
For generators with variable speed; the linear roll-off goes down to 18 Hz. There is also a ±5 V input for external control.
How fast does the MX321 respond?
The regulator response is 10 ms, the field current reaches 90 % in 80 ms and the machine voltage reaches 97 % in 300 ms.
Which regulator is fitted to the S7?
The MX341 is standard for the S7 and P7, and the MX322 for the S7 K-core and S7 Water-Cooled.
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