GE G60 Instruction Manual page 59

3 HARDWARE
V
a) Voltage with optional
current monitoring Voltage monitoring only
V
b) Current with optional
voltage monitoring Current monitoring only
c) No monitoring
Figure 3–13: FORM-A / SOLID STATE CONTACT FUNCTIONS
The operation of voltage and current monitors is reflected with the corresponding FlexLogic™ operands (
, , and
Op # Voff Cont Op # Ion Cont Op # Ioff
the voltage monitor is breaker trip circuit integrity monitoring; a typical application of the current monitor is seal-in of the
control command. Refer to the Digital Elements section of Chapter 5 for an example of how Form-A/SSR contacts can be
applied for breaker trip circuit integrity monitoring.
Relay contacts must be considered unsafe to touch when the unit is energized! If the relay contacts need to
be used for low voltage accessible applications, it is the customer's responsibility to ensure proper insula-
WARNING tion levels!
USE OF FORM-A/SSR OUTPUTS IN HIGH IMPEDANCE CIRCUITS
For Form-A/SSR output contacts internally equipped with a voltage measuring cIrcuit across the contact, the circuit
NOTE
has an impedance that can cause a problem when used in conjunction with external high input impedance monitor-
ing equipment such as modern relay test set trigger circuits. These monitoring circuits may continue to read the
Form-A contact as being closed after it has closed and subsequently opened, when measured as an impedance.
The solution to this problem is to use the voltage measuring trigger input of the relay test set, and connect the
Form-A contact through a voltage-dropping resistor to a DC voltage source. If the 48 V DC output of the power sup-
ply is used as a source, a 500 Ω, 10 W resistor is appropriate. In this configuration, the voltage across either the
Form-A contact or the resistor can be used to monitor the state of the output.
Wherever a tilde "~" symbol appears, substitute with the slot position of the module; wherever a number
sign "#" appears, substitute the contact number
NOTE
When current monitoring is used to seal-in the Form-A/SSR contact outputs, the FlexLogic™ operand driv-
ing the contact output should be given a reset delay of 10 ms to prevent damage of the output contact (in
NOTE
situations when the element initiating the contact output is bouncing, at values in the region of the pickup
value).
GE Multilin
~#a
I
If Idc 1mA, Cont Op xxx Von
~
~#b
otherwise Cont Op xxx Voff
~#c
~#a
If Idc 80mA, Cont Op xxx Ion
~
~#b
otherwise Cont Op xxx Ioff
I
~#c
~#a
~#b
~#c
) which can be used in protection, control and alarm logic. The typical application of
G60 Generator Management Relay
~#a
I
-
~#b
V
Load
~#c
+
Both voltage and current monitoring
~#a
V
-
~#b
I
Load
~#c
+
Both voltage and current monitoring
(external jumper a-b is required)
-
Load
+
3.2 WIRING
If Idc 80mA, Cont Op xxx Ion
~
-
otherwise Cont Op x Ioff
If Idc 1mA, Cont Op xxx Von
~
otherwise Cont Op x Voff
Load
+
If Idc 80mA, Cont Op xxx Ion
~
-
otherwise Cont Op x Ioff
If Idc 1mA, Cont Op xxx Von
~
otherwise Cont Op x Voff
Load
+
827862A1.CDR
,
Cont Op # Von Cont
3-11
3