CIRCUTOR EMF-EMB Series - Manual (Page 3)

----- Static switching modules EM ---------- M98116701-20 Pág: 2
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GENERAL DESCRIPTION
The EM series of static switching modules are the basic blocks used to build static capacitor
banks for power factor (PF) compensation. These static switched capacitor banks use thyristors
instead of electromechanical switchgears to connect and disconnect the capacitors. The static
system is the most convenient in case of large and fast fluctuations of the load current (load
changes lasting a few milliseconds to several seconds). The advantages of the static system are
the connection at zero voltage and the disconnection at zero current, thus avoiding transients. The
ON-OFF switching speed can be as high as 1 operation every 20 ms
Each EM module is used to switch ON and OFF a capacitor step. Notice that a fast power factor
controller like the COMPUTER...f must be used to regulate the power factor using a static
switched capacitor bank . The standard PF regulators aren't fast enough to compensate the fast
load fluctuations.
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TYPES
The range of static switching modules consists of four main groups :
• Three phase with fuses , designated as EMF-xx-xxx
•
Three phase without fuses , designated as EMB xx-xxx
Note: The symbol “x" means a reference number or character which depends on the type.
There are different types depending on the operating voltage and the power of capacitor they are
able to operate (see tables 1 to 4)
In the following paragraphs we designate generically as EM modules when we refer to general
or common characteristics valid for all the types.
TABLE 1.- Three phase EMF modules (Built in fuses)
CODE OPERATING
VOLTAGE
TYPE POWER
(kvar)
LOSSES
(W)
R41133 380-400V EMF-40/400 40 115
R41136 380-400V EMF-60/400 60 175
R41137 380-400V EMF-80/400 80 230
R41111 220-240 V EMF-25/230 25 125
R41112 220-240 V EMF-37,5/230 37,5 190
R41114 220-240 V EMF-45/230 45 225