Terminal equipment, connected to both power and telecommunications networks, is susceptible to power surges and transients from various sources: lighting discharges, high-load power-utility  and high-power electrical device switching, electrostatic discharges and electromagnetic disturbances. 

To safeguard sensitive terminal equipment during these stringent operating conditions, we have constructed a combined protection module with primary and secondary power surge protection.

TERMINAL EQUIPMENT PROTECTION MODULE

ELTEP 21-CS

 

                    

          

 

 

 

 

 

 

ELTEP 21-CS  PROTECTION MODULE

This is an over-voltage and over-current protection module for ISDN and ADSL terminal equipment connected to telecomunications and power networks.

Therefore, this module functionaly integrates two surge protection applications: terminal equipment power supply protection and ISDN/ADSL line protection. We also offer a model, ELTEP 21-CSR, with the telecommunication network and power network grounds isolated from each other.

 

 

 

  

 

 

 

Housed in a plastic case, it has the following connectors:

  • a three-pole power plug to insert into a 220VAC wall power outlet;

  • an external three-pole socket for terminal equipment power feeding;

  • an internal two-pole terminal block connector, for an additional 220VAC power cable     which can be inserted through a duct in the plastic case;

  • RJ45 jacks for telephone line and terminal eqipment.

 

The two protected 220VAC power sources feed an ISDN NT and an ADSL modem at the same time, so there is no need for two separate surge protectors at the customer premises.

The inside 220VAC connector is adapted for ISDN NT, and being "hard-wired", it prevents dislocation of the protection module to some other household electronic appliance.

Two light-indicators are placed on the front side, showing the status of the mains and the grounding condition respectively.

 

 

 

 

 

 

 

ISDN/ADSL Line Protection 

Over-voltage Line Protection 

There are two stages of ISDN/ADSL line over-voltage protection: primary and secondary. 

The primary, or coarse over-voltage protection is done by an EPCOS T25-A230X three-pole gas surge arrestor connected to the wire leads (a and b), with its middle pole tied to the mains earth. 

The secondary, or residual over-voltage protection is done by three Sibar C2600B75 diodes, one between the leads, and the other two between each wire lead and the mains ground. 

The two stages are separated by professional MELF resistors, dissipating 70W of power in less than 1ms. 

Over-current Line Protection 

At the front of the primary stage, two current/temperature dependent elements (PSW) are placed in the line, which, in case of over-current condition, disconnect terminal equipment from the telecommunication network.  

PSW elements are activated at power and telecommunication networks interactions, or during high voltage surges. Accordingly, they protect not just the terminal equipment but also the rest of the protection circuitry. 

After cooling down, the PSW elements reconnect the terminal equipment back onto the telecommunication network, thus performing the function of an automatic fuse.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Terminal Equipment Mains Power Supply Protection

 ELTEP 21-CS  offers two 220VAC, 50Hz mains power connections: external power socket and internal two-pole terminal block power connector. Both power sources use varistors for over-voltage protection.

 Varistor Over-voltage Protection

 Three 20D 471K varistors are used, connected the following way: phase-earth, neutral-earth, and phase-neutral

 

 

 

 

 

 

ELECTRICAL AND TECHNICAL CHARACTERISTICS OF THE PROTECTION AT THE TELECOMMUNICATION NETWORK SIDE

 

ELTEP 21-CS BASIC CHARACTERISTICS AND COMPONENTS

  • combined power surge protection of terminal equipment from harmful sources over power networks and telecommunication networks;

  • mains three-pole power plug;

  • external, protected 220VAC mains power socket;

  • additional, internal, protected 220VAC mains terminal block connector;

  • mains voltage indicator;

  • grounding fault indicator;

  •  telephone line jack;

  • NT jack;

  • ADSL modem jack (plus optional ADSL Combi Splitter).

 

 

Nominal voltage

130V

Max. voltage

£160V

Nominal current

£145mA

Nominal impulse voltage (wave 10/700 ms)

6 kV (a-PE, b-PE)

6 kV (a+b)-PE

Nominal impulse current (wave 8/20 ms)

2,5 kA (a/b-PE, a-b)

5 kA ((a+b)-PE))

Max. impulse current (wave 8/20 ms)

5 kA ((a+b)-PE))

5 kA (a/b-PE, a-b)

Clamping  voltage

< 600 V (a/b-PE)

< 300 V (a-b)

Upper frequency limit

> 2,0 MHz

Temperature range

-25 oC  +60 oC

Response time

£25ns (a/b-PE)

£1ns (a-b)

Connector

RJ45

 

 

 

 

 

 

 

 

 

 

ELECTRICAL AND TECHNICAL CHARACTERISTICS OF THE PROTECTION AT THE POWER NETWORK SIDE

 

 

Nominal voltage

230/50Hz

Max. voltage

280/50Hz

Nominal current

8 A

Nominal impulse voltage (wave 1,2/50 ms)

6 kV (L/N-PE, L-N)

10 kV ((L+N)-PE)

Nominal impulse current (wave 8/20 ms)

2,5 kA (L/N-PE, L-N)

5 kA ((L+N)-PE))

Max. impulse current (wave 8/20 ms)

5 kA (L/N-PE, L-N)

10 kA ((L+N)-PE))

Clamping voltage

< 800 V (L-N)

< 300 V (L/N-PE)

Clamping  voltage at 1kV/ms

< 1500 V (L/N-PE)

Temperature range

-25 oC  +60 oC

Response time

£25ns (L-N)

£100ns (L/N-PE)

Connector

DIN 49 440-CE(7)III

DIN 49 440-CE(7)IV

 

 

 

 

 

 

 

 

 

 

 

 

BILL OF MATERIALS 

  • Surge arrester EPCOS T23-A230X

  • Resettable fuse (PSW) RAYCHEM TS250-130-RA

  • Sibar diode CERAMATE C2600B75

  • Resistor Vishay MMB0207  3,3 OHM

  • Varistor 20 D 471K

  • Diode LED KP-3216LSURC

 

 

 

 

CONNECTION SCHEMES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
       
 
Address. Hrvatske Mornarice 1F 21000 Split Croatia | Phone. +385 21 32 36 70 | Fax. +385 21 32 36 72