Specifications

IGBT to Watts
board mounted trimmer potentiometer.
Isolated Gate Bipolar Transistor gate (IGBT) A power transistor
with a gate similar to the base of BJT. The difference is that the gate is
electrically insulated from the collector-emitter circuit. This allows high
voltages and currents to be conducted.
Jogging This feature provides a means of momentarily moving the
motor at a different speed (normally slower) from the normal operating
speed. Operators access this function using a separate control input.
Load A term used to describe work require form a motor to drive
equipment attached at the shaft. Usually defined in units of horsepower,
or torque at a certain speed.
MOSFET A Metal-Oxide-Semiconductor-Field-Effect-Transistor is simi-
lar to standard field-effect transistors. MOSFETs can be a N or P type.
They will or will not conduct from source to drain unless a voltage is
applied to the gate of the MOSFET. They have turn-on and turn-off
capability, as well as fast reaction times.
NEMA The acronym stands for the National Electrical Manufacturers
Association. The agency provides specification standards for motors and
drives.
Noise (EMI/RFI) Electrical disturbances that interfere with proper
transmission of electrical signals. Noise can have adverse effects on the
system performance.
Non-volatile Memory A memory storage system that maintains infor-
mation during the loss of power.
Ohm Unit of electrical resistance of a circuit in which a potential dif-
ference of one volt produces a current of one ampere.
Open-Collector An output signal, provided by a transistor, where the
“open-collector output” acts like a switch closure to ground when acti-
vated.
Open-Loop A system that does not use feedback information to regu-
late performance.
Phase Lock Loop (PLL) Used for error correction, PLL refers to an
external digital controller that monitors digital feedback proportional to
velocity. It compares that to a known number of counts that should be
seen within a specified time frame, and calculates error based on its
feedback. Minarik uses Phase Lock Loop on digital front-ends such as
the DLC Series.
PLC A programmable logic controller (PLC) uses programmed logic
instructions to control banks of inputs and outputs which interface timed
switch actuation to external electro-mechanical devices.
Plugging A method to provide quick stopping or reversing of a motor
by applying partial or full reverse voltage on the motor terminals during
operation. Not recommended for DC systems since the life of the motor
and drive reduces, while permanent damage may result.
Poles The magnetic poles in an electric motor that result from connec-
tion and placement of the windings in the motor. Besides poles created
by electricity, permanent magnets mounted in specific areas are poles
with a constant orientation.
Potentiometer (Pot) A passive device (variable resistor) used to vary
voltage between a minimum and maximum level. The standard speed
pot is a 300° or single-turn. Operators control the speed of a motor
from the potentiometer connected to a drive. Also, board-mounted trim-
mer pots allow users to make calibrations.
Proportional-Integral-Derivative The act of recognizing a velocity or
position error in a system, and applying correction (or voltage change) to
the system amplifier, thereby changing the motor’s speed or altering posi-
tion. PID refers to a group of gain parameters that tune or optimize the
response of a closed-loop system.
1. Proportional: This feedback loop compares error and adds an equal
amount of reference beyond the original. For example: with a 20% error,
the loop applies 20% more than the original reference.
2. Integral: This loop examines the average error over a number of sam-
ples, and makes the correction associated with it. For example: with a
20% error reading in one window and 10% error in another, the integral
loop may apply 15% error correction in the third window based on aver-
age of previous readings.
3. Derivatives: This loop reads instantaneous change in error, as
opposed to the error itself. It analyzes how an error differs from a previ-
ous error and adjusts accordingly. PID combines all three loops
resulting in an extremely accurate form of digital error correction.
Each loop checks and balances the other to assure the right amount of
error correction. Lead-Lag is similar to PI in correcting error through
known error and average error. The difference is that this can over or
under compensate, based on a trend or assumption of what is assumed
will occur in the next error. The error correction can lead or lag the actu-
al error.
Rated Values The rated value of a parameter (voltage, temp, etc.) is
the maximum value that the parameter can reach in an electric device
operating continuously without undue degradation, loss of its basic
properties, or safety hazards.
Regenerative Regenerative drives, often used interchangeably with
four quadrant drives, applies to the regeneration of energy from the
motor and drive, back to the power source. A motor generates when the
load forces the motor to go faster than the drive has set. Four quadrant
drives can prevent motors from over speeding. A four quadrant drive is
regenerative when it puts the generated energy back into the source, like
a battery or the AC line. Also, the energy could be dumped across a
dynamic brake resistor or a dump resistor, as is the case in a non-regen-
erative, four quadrant drive.
Relay These electronic components control other devices in a circuit. A
set of contacts, the switching mechanism, open or close when the relay’s
magnetic coil becomes energized.
Resistance The opposition to current flow through a conductor in a
closed circuit.
Rotor The rotating assembly of a motor. Usually includes a shaft, fan
and rotor core.
Silicon Controlled Rectifier (SCR) Also known as a thyristor, a SCR is
basically a diode with an extra junction tied to a third leg, known as the
gate between the cathode and anode. SCRs prevent current flow in either
direction until the gate receives a voltage signal. After receiving this trig-
ger signal, the SCR then becomes a diode. It remains on, regardless of
what happens at the gate, until the zero crossing, at which point current
cease to flow.
Servo A system consisting of an amplifier, actuator, and feedback ele-
ment. Servos tend to control one or combination of the following vari-
ables: position, velocity and torque.
Speed Regulation Defined as the deviation in motor speed from No
Load to Full Load; usually expressed as a percentage of base speed.
Feedback devices, like a tachometer or digital closed loop control, pro-
vide increased regulation.
Stator The stationary part of a motor. A PM DC motor holds its mag-
nets in the stator.
Surge Suppressors These devices, like a metal oxide varistor (MOV),
suppress voltage transients that can occur on the AC line.
Tachometer Feedback A tachometer (tach) generates a voltage pro-
portional to speed. Tachs provide a closed-loop system with excellent
speed regulation.
Torque A rotational force equal to an equivalent linear force applied
at a right angle to a radius of r.
Torque-to-Inertia Ratio The rated motor torque divided by its rotor
inertia. Helps determine a motor’s ability to accelerate loads.
Transformer A passive device that raises or lowers AC voltage by
induction.
TTL (Transistor-Transistor Logic) A popular family of integrated cir-
cuit devices that operate from logic level voltages, 5 to 12 VDC.
Voltage Voltage is electric pressure. A volt is a unit of electromotive force
which causes 1 Amp of current to flow through a 1 Ohm resistor.
Watts The power required to maintain one ampere of current at a pres-
sure of one volt when the two components are in phase with each other.
A unit of horsepower is equal to 746 watts.
Glossary
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REFERENCE