Opto F 3.0 / Opto F+E 3.0 / Alpha M, E — short-circuit indicators with fiber-optic isolation and flag type
Opto F 3.0, Opto F+E 3.0 and Alpha M, E are classic short-circuit indicators for medium-voltage switchgear. In Opto the signal goes from the sensors to the indication unit over optical fiber, while Alpha shows a short circuit with mechanical flags. Short-circuit settings are 400, 600, 800 or 1000 A.
- Opto F 3.0 — SC setting
- 400, 600, 800, 1000 A (on the sensor); delay 40–500 ms; accuracy ±15 %
- Sensor isolation
- fiber-optic cable between current sensors and the indication unit
- Opto F+E 3.0
- SC + earth fault for networks with a low-impedance/solidly earthed neutral
- Alpha M / E — SC setting
- 400, 600, 800, 1000 A; delay 100 ms; ±15 %
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The manufacturer presents both series in the section of other products. They are used first of all in the maintenance and extension of existing MV switchgear, including open-type switchgear. Opto F 3.0 detects, shows and remotely signals short-circuit currents in MV distribution networks and suits all cubicle types.
The main feature of Opto is galvanic isolation. Current sensors are installed on a cable, busbar or bare copper conductor, and each has a built-in threshold element. When the current reaches the setting, the sensor sends light pulses to the indication unit over a fiber-optic cable, so there is no electrical connection between the primary circuit and the unit. The short-circuit setting is chosen on the sensor, and the operating delay of 40–500 ms is set on the indication unit. Accuracy of ±15 % is determined by the sensor.
The indication is per phase, with bright LEDs. A single flash means a single excitation, typical for a radial network, and a double flash means repeated excitation within the reset time, as in a ring network with auto-reclosing. Remote signalling is provided by a relay contact, settings are made by DIP switches, and flush-mounted and surface-mounted housing versions are available. Opto F+E 3.0 additionally detects earth faults in networks with a low-impedance or solidly earthed neutral in a radial or open ring scheme. Summation sensors for it are made for settings from 10 to 160 A.
Alpha M and Alpha E show a short circuit with flags. Three bistable elements for phases L1–L3 switch from black to red and keep the display until reset. Settings are 400, 600, 800 and 1000 A, delay 100 ms, pulses shorter than 20 ms do not cause excitation, accuracy ±15 %. The potential-free remote signalling contact is rated for 230 V AC/1 A and 220 V DC/1 A.
Alpha M is reset with a rotary knob and stands out for durability, while Alpha E is reset by a button on the front panel or remotely. If the device is connected to current transformers already installed in the cubicle, it is calibrated at the factory for these CTs. For Alpha, current transformers are made for RMUs of ABB, Eaton/Holec, Ormazabal, Schneider Electric and Siemens, so old indicators in typical cubicles are replaced without reworking the primary circuits.
Technical specifications
| Opto F 3.0 — SC setting | 400, 600, 800, 1000 A (on the sensor); delay 40–500 ms; accuracy ±15 % |
|---|---|
| Sensor isolation | fiber-optic cable between current sensors and the indication unit |
| Opto F+E 3.0 | SC + earth fault for networks with a low-impedance/solidly earthed neutral |
| Alpha M / E — SC setting | 400, 600, 800, 1000 A; delay 100 ms; ±15 % |
| Alpha — indication | 3 bistable flags (black/red) L1–L3 |
| Remote signalling | 1 relay contact 230 V AC/1 A |
Request a price and lead time
Opto F 3.0 / Opto F+E 3.0 / Alpha M, E — short-circuit indicators with fiber-optic isolation and flag type. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 9030 33 70 00 |
|---|---|
| HS, 6 digits | 9030 33 |
| CN (EU) | 9030 33 70 |
| HTSUS (USA) | 9030 33 38 00 |
| China customs tariff | 9030 33 90 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Why does Opto F 3.0 have fiber-optic isolation?
The sensors on the cable or busbar pass the signal to the indication unit with light pulses, so there is no galvanic connection between them. The device can be installed in cubicles of any type, including open-type.
What short-circuit settings do Opto F 3.0 and Alpha have?
Both series are set to 400, 600, 800 or 1000 A with ±15 % accuracy. The delay in Opto is set within 40–500 ms, and in Alpha it is 100 ms.
Can Alpha be installed in an existing cubicle with current transformers?
Yes, in that case the device is calibrated at the factory for the installed CTs. For RMUs of ABB, Eaton/Holec, Ormazabal, Schneider Electric and Siemens, separate current transformers for Alpha are made.
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