Specifications

Deadband I Speed I Accel/decel
Some Minarik regenerative drives contain the deadband fea-
ture for applications requiring the ability to adjust the time that
elapses between current reversals. Adjustments to the dead-
band trimpot will alter the degree to which a motor resists
changes in shaft position at zero speed. It performs this func-
tion by applying a small AC voltage to the motor armature.
These application specific settings are present on most drives
as a convenience to users. The minimum speed trimpot (MIN
Speed) allows one to adjust output voltage to the motor when
the reference to the drive is at a minimum. The reference may
be 0 volts input with a 0-10 VDC signal, or with the main speed
potentiometer turned fully counter clockwise. To adjust mini-
mum speed to zero, turn the trimpot clockwise until the motor
begins to rotate. Turn it slightly counterclockwise until the motor
stops. Once completed, the drive will be unaffected by the volt-
age necessary to overcome static friction, the “dead zone” of
the motor. As soon as the reference voltage input rises above
zero, the motor will turn. If the application requires the motor
to continue rotating, even with a zero reference input, rotate
the MIN speed trimpot clockwise to the desired minimum
speed. The minimum speed is important in applications such as
conveyor ovens, where stopping the motor could damage the
product in the machine.
The maximum speed setting (MAX Speed) determines the fastest
motor speed allowable when the main speed pot (or reference
voltage) is at 100%. With this adjustment, we can overspeed
the motor slightly, or we can limit the speed below the motor
maximum speed rating. The MAX speed trimpot is especially
useful when we cannot attain the exact motor for our desired
speed. Simply use one that can go faster, and reduce the max-
imum speed setting during calibration.
These settings are often referred to as soft start and soft
stop. They are useful in applications that require the motor
to ramp up to set speed, and ramp down to a slower
speed; a filling machine conveyor is a good example.
Here we don’t want liquid in the containers to spill
because of abrupt changes in speed. These trimpots are
also useful in applications using an undersized motor due
to space constraints (centrifuges for example). A very slow
acceleration helps to avoid going into current limit as the
motor accelerates to set speed.
Turning the acceleration or deceleration trimpot clockwise
will lengthen the time it takes for the speed change to
occur.
DEADBAND
MINIMUM (MIN) & MAXIMUM (MAX) SPEED
ADJUSTABLE ACCELERATION & DECELERATION
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REFERENCE