Ingles

Should there be any doubt as to the sense of any of the windings, the following method can be used to determine the polarity of the secondaries. Terminals K and L are connected to a d.c., source of about 4 V and K and 1 to a polarized voltmeter as shown in fig. 4.1. The polarity is correct, if there is a positive deflection when the switch S is closed.

Fig. 4.1 – Instrument transformerterminals and polarity check (U, u, V and v apply to p.t`s)
The auxiliary supply and the blocking signals must be within the ranges of permissible variation given in the data sheet.
The maximum data stated in the data sheet for the signaling and tripping contacts may not be exceeded.
For correct operation it is essential that the frequency marked on the rating plate of the relay (50 or 60 Hz) bethe same as the power system frequency. If this is not case, the relay can be provisionally re-calibrated to the corresponding frequency on site (see section 6.9).
5. COMMISSIONING
5.1 Pre-commissioning checks
- The wiring checks according to section 4.2 must be concluded.
- The auxiliary supply must not be switched on.
- The plug-in S1 to S4 and the DIL switches S65 must be set asrequired for the application (fig. 9.2 and 9.3)
5.2 Inserting the relay and switching on the auxiliary supply
It is only permissible to insert or withdraw the relay with the auxiliary supply switched off! |

It is only permissible to switch on the auxiliary supply after the relay has been inserted. When this has been done, all the segments of the LED display are automatically tested i.e.four rectangles, then four stars and then four dots appear on the mode and values displays; the number of firmware version is then displayed for about 1 s. providing the self-checking arrangements do not discover a defect, the display disappears, the green stand-by LED lights and the stand-by signaling contact closes.
Should on the other hand there be a defect, it is signaled on the display, therelay cannot assume the stand-by state and correspondingly the green LED does not light (see section 6.5).
5.3 Relay controls
5.3.1 General
Two memories are concerned with the relay settings (modes 0 to 49 and 100 to 149); see tables 9.5.1 and 9.5.3):
-main memory (non-volatile; NOVRAM)
The settings in this memory are the operational settings, i.e. only settings in the main memorydetermine relay behavior.
-operation memory (volatile)
Whenever the relay is switched on or upon a special instruction (see section 5.3.6) the settings are copied from the main memory into the operating memory where it is possible to change them as necessary using the key-pad. The value display shows only the values in the operating memory.
The changed and unchanged values in the operatingmemory can be written from the operating memory into the main memory, i. e. They become the new operational settings; by entering a corresponding instruction (see section 5.3.6).
As supplied the MCX91. Relays have the settings (default values) listed in table 9.5.1 and 9.5.3.
5.3.2 Frontplate displays, key-pad
On the frontplate (see fig.9.1) there and two LED displays, one for the address(mode) of a setting or measurement quantity, the other for its value. The same displays are used for signaling functions which have picked up or have tripped (selected automatically with flashing display).
Functions are selected and settings made using the key-pad, which apart from the digits 0 to 9 also includes keys for the following instructions:
R Reset: for resetting the frontplatedisplays of protection signals and error indications and also latched trips (see also section 6.1).
M Mode: for keying in a function address (e.g. pick-up, timer etc.; see also section 5.3.4)
V Value: for keying in a setting (see also section 5.3.5)
E Enter: the action of selecting a mode or entering a setting is terminated by pressing the `enter` key (see also...