Purpose

Diode-resistor unit BDRM-50 (analog of BDZ) is intended for joint operation with cathodic protection stations (e.g. V-OPE-TM, V-OPED-M “KEDR”) to provide electrochemical protection of underground metal constructions (pipelines, cables, etc).
Features

BDRM-50 can be used:
- for current distribution from rectifier up to four not-interconnected underground metal constructions,
- as polarized drainage and regulated resistors with diodes to remove deleterious effect of communications with separate protection.
Principle of operation

Unit BDRM-50 operates jointly with cathodic protection stations for multiple-strand (up to 4 lines) pipelines.

By setting the appropriate resistance in the unit channels, it is possible to support on all lines the required protective potential close to that supported by the cathodic protection station on the main line.

Unit BDRM-50 ensures supporting the required protective potential on couplings and cables from a separate cathodic protection station as well as from the station operating jointly with the unit.
Operating conditions

Unit is intended to operate under the following climatic conditions: - the upper value of ambient temperature + 45 °C;
- the lower value of ambient temperature - 60 °C;
- the upper value of relative humidity 98% at 25 °C;
- atmosphere of I type and II type according to GOST 15150-69.

Climatic UHL modification of distribution category 1 according to GOST 15150-69; unit is designed to be mounted outdoors.
Conventions
Technical data

Parameter	BDRM-50-1-1X-UHL1
1. Maximum of channels	1
2. Parameters of a channel:
- channel rated current, A	50
- total resistance of regulated resistors, ohm	0,24±0,024
- rated value of a single regulating resistor, ohm	0,04±0,004
- number of regulating resistors, pcs	6
- channel resistance regulation range, ohm	0-0,24
- permissible inverse voltage, V	1000
3. Specified life with probability 0.9, not less than, hours	100000
4. Mean-time-between-failures, not less than, hours	25000
5. Guaranteed service life, years	2,5
6. Weight, kg, not more than	17,6
7. Overall dimensions, mm, not more than	400х268х500
8. Capacity, dm3	53,6

Notes:
Parallel operation of channels of similar conduction is permitted. Channel resistances of each should be equal and not less than 0.02 ohm.

The unit has protection against lightning strokes.

The unit corresponds to 01 GOST 12.2.007.0-75 in the way of man protection against current injury.

The unit corresponds to fire safety requirements (GOST 12.1.004-91).

Specified service life – 20 years.

Guaranteed service life – 30 months.
The unit corresponds to the standards GOST R 51164-98, GOST 9.602-89, technical specifications IZHSK.656131.001TU.
The unit intended for export additionally meets the requirements RD 1601.007-88.
Construction

The unit is allocated in the case of carcassless type. There is a door with a lock at the front panel of the case.

The cooling of the unit is natural by air.

To ensure the cooling of the unit there are vent holes in the lower part and a special cover in the upper part of the case.

The unit’s level of protection is IP43 according to GOST 14254-96.

In the lower outer part of the case there is a clamp for connection of the unit to the grounding circuit.

The unit BDRM-50-1-1X-UHL1 has one channel.

The channel of the unit has:
- six identical wire resistors;
- diode that provides the required current direction in protected construction;
- shunt intended for measuring the channel current value with the help of portable device;
- jumpers used to regulate channel resistance or to shunt channel diode.

The channel is mounted on heat-resistant electrically insulating panel. The panel is installed on battens inside the case.

The required current value on the protected underground construction is provided by changing of channel resistance by switching of jumpers.

Construction of the unit ensures the possibility to produce it with a channel of forward conduction where cathode of diode is connected to the unit input in every channel, and with a channel of reverse conduction where anode of diode is connected to the unit input in every channel.

Units BDRM-50-1-1X-UHL1 are mounted on the horizontal base (foundation, frame, etc.).

Construction of terminal clamps provides connection of terminated wires and cables as well as cables without termination.

The branch pipe compression shall be done with polyurethane foam. Overall and installation dimensions

Designation	Type	Dimensions, mm								Weight, kg
		А	А1	В	В1	L	L1	H	d
IZHSK.656131.005	BDRM-25-4-30-UHL1	375	200	250	268	400	782	500	-	17,6
-01	BDRM-25-4-31-UHL1