Eaton Cutler-Hammer FP-5000 Instructions Manual page 102

Page 6-4
To minimize problems with Ct saturation during faults, keep the Ct
wiring as short as possible and use very heavy wire. The total
resistance of the connecting wire should not be much larger than
the secondary resistance of the Ct itself. The FP-5000 presents
very low burden.
Every phase and ground Ct circuit must have one and only one
grounding point. Figure 6-8 shows the common neutral connection
of the three-phase Cts, and the ground fault Ct, connected at one
point to a non-current-carrying ground. Do not use a neutral or
current-carrying conductor for this grounding – the noise will disrupt
FP-5000 measurements.
Residual connection of the phase Ct secondaries to form a ground
current signal will not give sensitivity approaching that of the flux-
canceling ground Ct.
6.3.2 VT Wiring TB2
Wiring of the VTs into the FP-5000 phase voltage input terminals
can be achieved several ways. Figure 6-8 gives a common example
of the VT Wye wiring. In Figure 6-9, a Delta configuration is
implemented using only two transformers, saving cost, weight and
size. The transformer polarity indicated by polarity dots must be
carefully considered when designing the VT into the system. It should
be noted that the secondary side of the transformer center tap is
tied to common, input VB (+) terminal 214, and VG terminal 218.
It should be noted that an FP-5000 can accommodate a reverse
phase sequence providing that phase voltages and current are in
sync. (See Section 5.)
CAUTION
TERMINAL TB218 VG IS INTERNALLY REFERENCED TO
GROUND THROUGH A CONTROLLED IMPEDANCE TO THE
FP-5000 CHASSIS. THE VOLTAGE TRANSFORMER SECONDARY
RETURN MUST BE PROTECTIVE EARTH GROUNDED AND
TB218 CONNECTED TO THIS RETURN. TB218 VG MUST NOT
BE CONNECTED TO PHASE OR NEUTRAL CONNECTIONS.
6.3.3 Output Contact Wiring TB1
See Section 3 Specifications for ratings of output contacts, and
check against controlled loads.
Figures 6-8 and 6-9 show typical connections of FP-5000 output
relay contacts in control circuits. However, the outputs are com-
pletely programmable, so there can be numerous choices in
selecting and using these outputs for tripping, alarming and
auxiliary control.
The installation design engineer should refer to Sections 5 and 9 to
understand the available output functions and programming options.
It is recommended to record and confirm the settings, and also
design a consistent connection of the contacts of the output relays
to the control system.
6.3.4 Supply Wiring TB1
Refer to Figure 6-8 or 6-9. Connect terminals 101 and 102 to a
source of control power rated at either 100 –120V AC or 48–125V
DC. Nominal values other than these voltages are not acceptable.
However, the FP-5000 is capable of handling depressions, dips, and
limited sustained variations in the normal course of service. See
Section 3 Specifications.
6.3.5 Contact Input Wiring TB2
The optically isolated contact inputs are "dry contact inputs." The
actuating or wetting voltage is provided by the FP-5000. Each input
is activated by connecting it through an appropriate contact to the
provided voltage. The return, common connection, or DC negative
rail associated with the "wetting voltage" is internal only and is not
provided to the user (See Figure 6-9). The wetting voltage and
current requirements of the external contacts should be reviewed for
compatibility with the FP-5000's 40V DC source voltage and 2mA
current draw. The particular contacts to be connected depend on the
settings programmed in the FP-5000. There is a complete list of
functions which can be assigned to each of these inputs.
The engineer designing the installation should study Sections 5 and
9 to understand and designate the use, if any, of the discrete contact-
sensing inputs assigned to each input.
The discrete input circuits (Cin1 – Cin8) are totally isolated from the
other circuits in the FP-5000. Supply or wetting voltages (40V DC)
are located on terminals [C in source 1] and [C in source 2] (TB 205/
210) and return is through each input. Wetting current is limited to
~2mA per input. There are no external connections for common or
return for these circuits.
CAUTION
BEWARE OF LARGE SHUNT CAPACITANCE ACROSS
CONTACTS OR IN SOLID-STATE RELAYS CONNECTED TO THE
FP-5000 DISCRETE INPUTS. CHARGING CURRENT THROUGH
THE CAPACITOR COULD CAUSE A FALSE INDICATION OF A
CLOSED CONTACT. KEEP TOTAL CAPACITANCE BELOW 0.05
MICROFARADS.
6.3.6 Terminal Identification
This section offers a brief description of the terminals mounted
on the rear of the outer case. The terminal designators are TB1,
TB2, TB3, and Ct connector TB4. Refer to Figure 6-4 and 6-5
FP-5000 Rear Terminal Designations.
Power Supply and Relay Contacts (TB1)
The power supply terminals are 101 and 102. There are 5 Form A
normally open relays each with their own independent common, and
2 Form C normally open, normally closed relays each with their own
independent common. These relays can be tested as well as reset
when in the test mode as mentioned in Section 11.2.5.2. Refer to
Figure 6-4 FP-5000 Rear Connections and Table 3.1 Table of
Specifications for relay terminal numbers and relay electrical
characteristics.
Cin1 – Cin8 (TB2)
Terminals 201–210 of terminal block TB2 are used in programmable
logic applications. Default settings are set at the factory to provide
standard operational functions. Cin1 – Cin8 are used as contact
inputs when the "Contact Input" option category is selected. For
more detailed information, refer to Section 9, "Programmable Logic
Application."
IL17569
Effective June, 2001