SJ700
2
Inverter
Oper
ati
ons
and Monitor
ing
4–23
Switching to inverter control occurs after the motor is running at full speed. First, Mg2 relay
contacts open. Then about 0.5 to 1 seconds later, relay Mg3 contacts close, connecting the
inverter to the motor. The following timing diagram shows the event sequence:
In the previous timing diagram, when the motor has been started across the line, Mg2 is
switched OFF and Mg3 is switched ON. With the Forward command to the inverter already
ON, the [CS] terminal is switched ON and relay Mg1 contacts close. The inverter will then read
the motor RPM (frequency matching). When the [CS] terminal is switched OFF, the inverter
applies the
Retry wait time before motor restar
t parameter (B003).
Once the delay time has elapsed the inverter will then start and match the frequency (if greater
than the threshold set by B007). If an over-current trip occurs during frequency matching,
extend the retry wait time B003. If the ground fault interrupter breaker (GFI) trips on a ground
fault, the bypass circuit will not operate the motor. When an inverter backup is required, take
the supply from the bypass circuit GFI. Use control relays for [FW], [RV], and [CS].
Software Lock
When the terminal [SFT] is ON, the data of all the parameters and functions (except the output
frequency, depending on the setting of B031) is locked (prohibited from editing). The keypad
and remote programming devices will be prevented from changing parameters. To edit parame-
ters again, turn OFF the [SFT] terminal input. Use parameter B031 to select whether the output
frequency is excluded from the lock state or is locked as well. Note the following:
• When the [SFT] terminal is turned ON, only the output frequency can be changed.
• Software lock can include the output frequency by setting B031.
• Software lock by the operator is also possible without the [SFT] terminal being used (B031).
Mg1
Mg2
Mg3
FW
[CS]
Mg2/Mg3 delay time 0.5 to 1 sec.
Set to 0.5 to 1 sec. typical
Frequency matching
Inverter
output
Normal operation
B003 (Retry wait time
before motor restart)
Opt. Code
15
Symbol
[SFT]
Valid for
Inputs
[1] to [8]
Required
Settings
B031
(excluded
from lock)
Default
terminal
Requires
config.