I-GARD GCHK-100 Instruction Manual
10
Table 7.5 GROUND CHeCk SeTTiNGS
function
1
2
3
4
5
6
7
10 Ohms
0
0
20 Ohms
0
X
30 Ohms
X
0
*50 Ohms
X
X
Note:
actual *level includes the impedance of the zener diode as well as the wire resistance.
Note:
X indicates switch is on.
The TRIP relay will operate when the ground loop resistance exceeds the setting for a period exceeding 150 ms
to 300 ms. Also the R
G
indicator LED will light on the relay and remote indicators, if installed.
The current Ground Check resistance can be monitored using the mGARD-SYM remote indicator. The indicator
displays the ground resistance as a percentage of the current trip level. A Ground Check trip can be seen on
both the mGARD-SYM and on the GCHK-DRI (red LED will light).
frame Voltage operation
To provide a greater degree of operator protection, a voltage sensing function is included in the operation of the
GCHK-100 relay to detect if the frame to ground voltage of the mobile equipment has exceeded preset levels.
The voltage detection will operate within 100 ms (quicker than the ground check resistance detection) and within
30 ms if the frame voltage exceeds 100V AC. The intent is to provide a greater safety margin for the operator
and others in the vicinity of the equipment.
Frame Voltage can be monitored using the mGARD-SYM remote indicator. The indicator displays the Frame
Voltage as a percentage of the current trip level. A Frame Voltage trip can be seen on both the mGARD-SYM and
on the GCHK-DRI (red LED will light).
A flashing V
G
light indicates a thermal overload, due to an elevated frame voltage (greater than 30 VAC, for
an extended period of time). The relay cannot be reset until it cools down to an acceptable internal operating
temperature.
Note:
for higher frame voltages, the built in fuse may open prior to the thermal overload tripping. Replacement fuse type should be
Buss FNQ-1⁄2 or equivalent 1⁄2 A time delay fuse.
Summary of Contents for GCHK-100
Page 20: ...the power to protect...
