BECKWITH ELECTRIC M-3425A, Instruction Book

Page: 347 / 482

M‑3425A Instruction Book
6–60
87 Phase Differential (#1 or #2)
VOLTAGE INPUTS:
None
CURRENT INPUTS:
Configuration C3
TEST SETTINGS:
Minimum Pickup P Amps (0.20 to 3.00)
1 Amp CT Rating (0.04 to 0.60)
Percent Slope S % (1 to 100)
Time Delay D Cycles (1 to 8160)
CT Correction (0.5 to 2.0)
Programmed Outputs Z OUT (1 to 8)
Expanded I/O (9 to 23)

NOTE
: Although a voltage input is not required for the testing of the 87 function, it is suggested that Nominal
Voltage be applied to restrain the functions which use both voltage and current inputs for operation.
Test Setup:
1. Determine the Function 87 Phase Differential settings to be tested.
2. Enter the Function 87 Phase Differential settings to be tested utilizing either the HMI or IPScom
®
Communications Software.
3. Disable all other functions prior to testing. Refer to Section 4.4 System Setpoints, for details that
describe disabling/enabling functions.
4. Connect test current inputs as shown in Figure 6-5, Current Inputs: Configuration C3.
Minimum Pickup Test
:
1. Set Current Input 1(I
a
) to 0 Amps.
2. Press and hold the
TARGET RESET
pushbutton, then slowly increase Current Input 2 (I
A
) until
the
PHASE DIFF CURRENT 87
LED illuminates, or the function status indicator on the
Monitor
Function Status
screen indicates that the function has picked up.
The current level of operation will be equal to
P
amps ±0.1 A or ±5%.
3. Release the
TARGET RESET
pushbutton, then decrease the Current Input 2 (I
A
). The
OUTPUT
LED(s) will extinguish.
4. Press
TARGET RESET
pushbutton to reset targets.
5. Repeat Steps 1,2,3 and 4 for each remaining phase exchanging I
A(B,C)
and I
a(b,c)
as appropriate.
Timer Test
:
1. Connect a timer to output contacts
(Z)
so that the timer stops timing when the contacts
(Z)
close.
2. Apply a current level to Current Input 2 (I
A
) at least 10% greater than the minimum current pickup
level and start timing. The contacts will close after
D
cycles within

1 cycle or ±1%. When the Time
Delay is set to 1 cycle, the relay operation is less than 1-1/2 cycles.