PARALLELING
There are no provisions on the CV 500-I to permit par-
alleling.
DIODE OPTION
(Factory installed only)
The CV 500-I Diode option is required to utilize the
cold start and cold electrode sensing features of the
NA-3, NA-5 or NA-5R. When this option is not used
with an NA-3, NA-5 or NA-5R, see the CV 500-I /
NA-3, CV 500-I / NA-5 or CV 500-I / NA-5R connection
diagram for instructions on how to disable this circuit.
If the circuit is not disabled, the wire cannot be inched
down.
METER OPTION
Factory installed Ammeter and Voltmeter
Machine & Circuit Protection
(Thermal Protection Light)
The power source is thermostatically protected with
proximity thermostats against overload or insufficient
cooling. One thermostat is located on the nose of the
center bottom primary coil and a second thermostat is
attached to the lead connecting the secondaries.
Both thermostats are connected in a series with the 2-
4 circuit. If the machine is overloaded, the primary
thermostat will open, the output will be zero, and the
thermal protection light will be on; the fan will continue
to run. The secondary thermostat will open either with
an excessive overload or insufficient cooling. The out-
put will be zero and the protection light will be on; the
fan will continue to run. When the thermostats reset
the protection light will be off.
The power source is also protected against overloads
on the SCR bridge assembly through an electronic
protection circuit. This circuit senses an overload on
the power source and limits the output to 550 amps by
phasing back the SCRʼs.
Protection is provided to protect the circuitry from
accidental grounds. If the customer accidentally
“grounds” 75, 76, or 77 to the positive output lead, the
output will be reduced to a low value, thus preventing
any damage to the machine. If the ground occurs
between 75, 76, 77 and the negative output lead, one
of the PC board “self-restoring” fuses will blow, pre-
venting any machine damage. After the ground is
cleared, the fuses automatically reset within a few
seconds.
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