Trasformatori elettrici
Stabilizzatori di tensione
Convertitori di Frequenza
UPS, Inverter, Alimentatori
I dati tecnici riportati sono solo indicativi e possono essere variati in qualsiasi momento senza alcun preavviso
K-FACTOR SRL unipersonale - Via Giotto 9
–
42014 Castellarano (RE) Italy - C.F. e P.IVA (VAT#) IT 02422010369
R.E.A. di RE n. 286968
–
C.S.
€
10.000,00
–
N. Iscrizione Reg. Imprese di RE: 02422010369
Tel +39-0536261380
–
e-mail: [email protected] - http://www.kfactor.it
01
ISO9001
- Devices for thermal control of resin or dry transformers
o Overload protection due to overloads are generally carried out with automatic circuit breakers that, in addition to the
magnetic relay, have a thermal relay that works for the deformation of a metal sheet subjected to heating as a function
of the current circulating in the circuit. The thermal relay is particularly suitable for overload protection, working with
sensitive delay with respect to magnetic relays, to prevent transient loads.
o Resin and dry transformers on each column at the hottest point can be fitted with a PT100 type thermal resistor with
the contacts shown in the terminal box. Thermocouples are then connected to a temperature control and display unit
equipped with contacts that can be set for alarm and trip. See manual electronic control unit for connecting it
8. OPERATION
The rated power of a transformer is referred to, according to the EN standards, an altitude below 1000m. at sea level, at
a maximum ambient temperature of 40 ° C and the maximum overtemperature of the classes of insulating materials
8.1 CURRENT
The load current must be sinusoidal
8.2 BALANCED LOAD
It is good that the load is evenly distributed over the three phases, however, if necessary, the phase currents may be
different, provided that none exceeds the nominal rating plate.
8.3 PARALLEL OPERATION
For a proper parallel, the following conditions must be met:
- Relationship Equation turns to all input voltages (or switch positions, if present)
- Connection Group Equality
- Equality of short-circuit voltage.
The parallel operation of the transformers will be better as far as the power of the transformers is similar.
It is therefore not advisable to operate in parallel with power ratios greater than 1/2.
After performing two or more transformer parallel connections, check that the corresponding terminals of AT and BT are
connected at the same time before they are energized and that the switches, if any, are in the same position as the same
ratio of transformation.
Before closing the parallel on the secondary bars, parallel testing is indispensable.
To do this, it is necessary to create, among the transformers secondary, a metallic joining bridge that makes comparing
the phase voltages possible.
When the neutral is present, the metallic connection is appropriate.
Using a voltmeter, the value of the potential difference between
c’
L1 - b'L2 - a'L3 must be checked. If this value is
consistently zero, it means that all parallel conditions are met, and the low voltage switches can be closed. The installation
and connection of 2 or more parallel transformers must always be carried out by people with technical or experience
knowledge or persons who have received specific instructions enough to prevent the dangers of electricity
