Selective Calling

can a cell phone number be added to a selective call forwarding list on a residential phone?

I have been unable to add cell phone numbers to my residential selective call forwarding. land line numbers are no problem only cell numbers. The system will not upload them.

The cell phone number can be added. You must type in the full 10 digit number and don’t forget 1 in the beginning if the problem still persists then call your phone service provider.

COBRA MR F75-D MARINE CLASS-D DIGITAL SELECTIVE CALLING TECHNOLOGY FIXED MOUNT R $153.72

COBRA MR F75B-D MARINE CLASS-D DIGITAL SELECTIVE CALLING TECHNOLOGY FIXED MOUNT $153.22

COBRA MR F80B-D MARINE CLASS-D DIGITAL SELECTIVE CALLING TECHNOLOGY FIXED MOUNT $169.95

COBRA MR F75-D MARINE CLASS-D DIG SELECTIVE CALLING TECH FIXED MOUNT RADIO WHITE $149.95

Cobra Mr F80B-D Marine Class-D Digital Selective Calling Technology Fixed Mount $169.95

Cobra Mr F75B-D Marine Class-D Digital Selective Calling Technology Fixed Mount $149.95

Cobra Mr F75-D Marine Class-D Digital Selective Calling Technology Fixed Mount $149.95

COBRA MR F75B-D MARINE CLASS-D DIGITAL SELECTIVE CALLING FIXED MOUNT $167.87

PYE Selective Calling Unit UK Military MOD 5820-99-742-8187 DIGITAL OUTSTATION $59.95

What is the selectivity?

The average selectivity of protection devices is also known by other terms such as discrimination or the coordination of protective devices.
In short order, coordination means that intermediate devices (circuit breakers / fuses) should activate before upstream devices. This minimizes the system affected by a fault or other disturbances. At the substation,
power switches must trip before the primary.

Also, the rear panel circuit breakers trip before the substation feeder supplying of the panel.

There are two levels of selectivity:
• Total selectivity
• partial selectivity

Total selectivity

Selectivity is said to be total if the downstream circuit breaker or fuse circuit breaker is opened and closed upstream. This ensures maximum protection system availability.
The total selectivity is achieved if the selectivity is ensured for the operation time interval t ≥ 0.1 s (time of the characteristics old) and also for operation time range t
The selectivity is achieved if performance I2t maximum values of upstream protective device is greater that I2t value of downstream protective device.

The first case of total selectivity: the protective devices are fuses.

Second case total selectivity: the protective devices are MCCB.

Partial selectivity

The selectivity is partial if the above condition not satisfied until the future stream of short, but to a lesser value, called the selectivity limit current (s). Above this value both protective devices could open, resulting in loss of selectivity. In most cases it is questionable selectivity in the operation times t
The first case of the selectivity partial protection devices are MCCB and fuses.

How to achieve selectivity in MCCB

In general, three methods used:

1. The selectivity based on current levels
This method is done by setting thresholds trip relay successive levels staggered intermediate devices (lowest value) to the source (higher settings).

2. On the basis of selectivity step delays
This method is implemented by adjusting the shutter delay time units, so that the intermediate relays should have shorter operating times, with the increasing time delays to the source.

3. Selectivity based on a combination of methods 1 and 2 A mechanical time delay added to a regimen Current level can improve the overall performance of selectivity. With this method you can achieve total selectivity.

The selectivity in practice

In systems where selectivity is not considered to occur unnecessary energy losses in parts of the circuits where the protection should not disconnect.
The previous case (the sample) can be in short circuit fault bars below FA2 protection device (1) disconnect fuse FU1 (3) and all loads fed by the TRF1 is without power supply. These cases do not want to happen in the industry and are especially problematic in systems where availability supply of energy required (hospitals).

Methods of conducting a study of the selectivity of

Method usual for a study of coordination used by the designer is the comparison of time-current curves of software that allow the designer to select the curves of the data libraries of manufacturers of protective devices.
TSI offers ETIFUSE program. This software calculates the time of operation, cutting currents and Joule integral for ETI fuse links. Programs allow users to easily verfy selectivity of protective devices of the TSI. Schedule can download and install from the internet at: www.eti.si / Support

Selectivity table for protection devices and Etibreak ETI Etimat

Boxes containing the letter "T" indicates the total selectivity between the circuit upstream and downstream relevant machines or other protective devices. Total selectivity applies to all levels of blame to the breaking capacity of the
breaker upstream or downstream, whichever is less. For all other cases, the selectivity is partial or no selectivity.
If the selectivity is partial, then the value of the selectivity limit current.

TSI has renewed the program of MCCB recently and also offer wide range of microprocessor based electronic MCCB. These will offer MCCB
customer in view of selectivity very flexible solution.

href = "http://www.eti.si/en"> more

About the Author:

Article Source: ArticlesBase.com – New Series of Etibreak Eb2 in View of Selectivity