Mitsubishi Electric 800 Series Instruction Manual page 369

• Inverter operation is sometimes hindered by the size of the moment of inertia (J) of the load or the output frequency. Adjust
this coasting time within the range 0.1 to 30 seconds to match the load specification.
 Adjustment of restart operation (Pr.611)
• Using Pr.611, the acceleration time to reach Pr.20 Acceleration/deceleration reference frequency after a restart
operation can be set. This can be set individually from the normal acceleration time.
NOTE
• Changing the Pr.21 Acceleration/deceleration time increments setting does not affect the Pr.611 setting increment.
• A PM motor is a motor with interior permanent magnets. Regression voltage is generated when the motor coasts at an
instantaneous power failure or at a flying start. The inverter's DC bus voltage rises if the motor coasts fast or makes a flying
start in this condition.
When using the automatic restart after instantaneous power failure function (Pr.57 ≠ "9999"), it is recommended to also use
the regenerative avoidance function (Pr.882 Regeneration avoidance operation selection = "1") to make startups stable. If
the overvoltage protective function (E.OV[]) still occurs with the regeneration avoidance function, also use the retry function
(Pr.67).
• When a built-in brake or a regeneration unit is used, the frequency search may not be available at 2200 r/min or higher. The
restart operation cannot be performed until the motor speed drops to a frequency where the frequency search is available.
CAUTION
• A PM motor is a motor with interior permanent magnets. High voltage is generated at motor terminals while the motor is
running.
Do not touch motor terminals and other parts until the motor stops to prevent an electric shock.
• When the automatic restart after instantaneous power failure function is selected, the motor suddenly starts (after reset
time passes) when an instantaneous power failure occurs.
Stay away from the motor and machinery.
When the automatic restart after instantaneous power failure function has been selected, apply the CAUTION sticker(s),
which are found in the Inverter Safety Guideline enclosed with the inverter, to easily visible places.
Parameters referred to
Pr.13 Starting frequencypage
Pr.65, Pr.67 to Pr.69 Retry
Pr.78 Reverse rotation prevention
Pr.882 Regeneration avoidance operation
368
14.(A) Application Parameters
14.8 Automatic restart after instantaneous power failure / flying start with a PM motor
175, page 176
functionpage 216
selectionpage 199
selectionpage 400