B481
OTHER: - Electrical - Definitions, Acronyms & Algorithms
- Definitions and Algorithms related to electrics.
Note: The algorithms are in blue
Ref. Symbols are in Times New Roman 2 sizes up from smallest. Subscripts are increased one size. See: Access database for procedures running the algorithms and for additional information.
Source for Symbols
[Source - PMMT]
Ampere: (
A)
- Electric current.
Anisotropic Material:
- Magnetic anisotropy: ~ The magnetic moment of a system is a measure of the strength and the direction of its magnetism. More technically, the term magnetic moment of a system usually refers to its magnetic dipole moment, and quantifies the contribution...
in zero field, while a magnetically anisotropic material will align its moment to an easy axis. Ref [PMMT p.360]
Armature:
- The rotating member of a motor with commutators. I.e. a brushed DC motor. Apparently, 'Armature' does not apply to brushless DC motors.
Axial Flux Machine: (Disk Type Machine)
Armature Reaction Effect:
- [See ~ EMDPS p.113]
Back EMF:
Voltage generated when a permanent magnet motor is rotated; a limiting factor for the high speed torque output of a permanent magnet motor as it is opposite in polarity to the supplied voltage and directly proportional to motor speed.
Bandage:
- See Magnet Bandage below.
Bipolar Switching: [Motor control]
- A drive that is capable of driving phase current in both directions. A current of either polarity (+ or -).
Breadth Factor:
Brushless DC motor (BLDC):
- A DC electric motor that uses an electronically controlled commutation system, instead of a mechanical commutation system.
- In a BLDC motor, the brush-system/commutator assembly is replaced by an intelligent electronic controller. The controller performs the same power-distribution found in a brushed DC-motor, only without using a commutator/brush system. The controller contains a bank of MOSFET devices to drive high-current DC power, and a microcontroller to precisely orchestrate the rapid-changing current-timings. Because the controller must follow the rotor, the controller needs some means of determining the rotor's orientation/position (relative to the stator coils.) Some designs use Hall effect sensors to directly measure the rotor's position. Others measure the back EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors, and therefore are often called "sensorless" controllers. (The BLDC motor has a trapezoidal backemf, while a brushless AC motor has a sinousoidal backemf.).
- http://en.wikipedia.org/wiki/Brushless_DC_motor.
- Electropaedia
Brushless Motor Types:
An alternating-current motor in which a primary winding on one member (usually the stator) is connected to the power source, and a secondary winding on the other member (usually the rotor) carries only current induced by the magnetic field of the primary.
Permanent Magnet: x
Switched Reluctance: Answers. com
Capacitance:
(C) [farads]
- The property of a circuit element that permits it to store charge.
Carter Coefficient: (kC)
Circuit Schematic Symbols:
Closed Loop Speed Controller: (Feedback Speed Controller)
Controller measures the speed of the motor.
Coercivity: Coercive Field Strength: (Hc)
- Materials with high coercivity are called hard ferromagnetic materials, and are used to make permanent magnets.
- A material with a low coercivity is said to be soft and may be used in magnetic shielding etc.
Cogging Torque:
Coil:
- A wound spiral of two or more turns of insulated wire, used to introduce inductance into a circuit.
- The electrical conductors wound into the core slot, electrically insulated from the iron core. These coils are connected into circuits or windings, which carry independent current.
- Coils have two electrical properties, namely resistance and inductance.
- Coils in motors are most commonly composed of multiple turns of round insulated wire. The centermost circle is the bare conductor. The next outer layer is the wire insulation, which is commonly available in three thicknesses, single, double (or heavy), and triple. The final outer layer is an optional layer of bonding material. This bonding layer is commonly composed of an adhesive that serves to bond layers of wire together after coils are formed.
Coil Pitch:
Conductivity: (σ)
- The ability to conduct electricity or heat.
Electrical conductivity ~ Materials
Constants:
- RPM Constant. [KV] See 'RPM Constant' below.
- Torque Sensitivity. [KT] [V/Krmp] See 'Torque Sensitivity ' below. ?
- Torque Constant. [
- Motor Constant. [
Contactor:
- A contactor is an electrically controlled switch used for switching a power or control circuit. A contactor is controlled by a circuit, which has a much lower power level than the switched circuit.
Core:
- The iron portion of the stator and rotor made up of cylindrical laminated electric steel. The stator and rotor cores are concentric and separated by an air gap.
Coreless Trapezoidal Stator:
Axial Flux motor. See [Source ~ AFPM p.35]
Coulombs:
(C) is the SI unit of electric charge
- Electric charge.
- One coulomb is the amount of electric charge transported in one second by a steady current of one ampere.
1C = 1A * 1sec
- One coulomb is the amount of charge stored by a capacitance of one farad charged to a potential difference of one volt:
1C = 1F * 1V
Current - no-load: [I0]
- Current across the motor terminals at no-load.
In Access database ~ Motor - Specifications.
Cycloconvertor:
A cycloconverter or a cycloinverter converts an AC waveform, such as the mains supply, to another AC waveform of a lower frequency, synthesizing the output waveform from segments of the AC supply without an intermediate direct-current link. http://en.wikipedia.org/wiki/Cycloconverter
Damper:
- The capacity built into a mechanical or electrical device to prevent excessive correction and the resulting instability or oscillatory conditions.
Delta Connection:
- A 3-phase connection where windings are connected in series with the power applied to, or taken from, the junctions (contrasted with star or Y connection). Delta is for higher RPM output.
- Polygon
is a delta type of connection with more than 4 phases.
Diameter Ratio (λ):
- The ratio of the inside diameter of the rotor? over its outside diameter.
Diamagnetism:
- The property of an object which causes it to create a magnetic field in opposition of an externally applied magnetic field, thus causing a repulsive effect.
Dielectric:
Direct Axis: (D-axis)
xx
Drum Type Winding: (Toroidal)
DSP board:
An acronym for Digital Signal Processing Board.
Eddy Current: (Foucault current)
Electrical Angle:
- The electrical angle = N/2 * mechanical angle. N is the number of poles.
Electrical Degree:
- A time interval equal to 1/360 of the time required for one complete cycle of alternating current.
Electromagnetic Induction:
Electromagnetic Force: Lorentz force
Electromagnetic shielding:
Electromotive Force [EMF];
- Give rise to current in an electrical circuit.
- EMF constant [kE] = cEΦ f . Where Φ f is Excitation magnetic flux.
- Armature constant (EMF constant) [cE]
Electronic Gearing:
- The ratio of one mechanical 360º to one electrical 360º.
Electronic Power Converter [EPC]:
- An electronic device for changing power in one of the following ways: AC/DC power converters, DC/AC power converters, AC/AC power converters, or DC/DC power converters.
Electrotor:
- A combined electric motor, gearing if required, and aero-rotor for a rotorcraft. The blade pitch control may or may not be electrical.
End Windings:
- The copper wire of the coil outside of the slot and perhaps that outside of the plane of the permanent magnet for slotless windings?
- Results in higher copper loss.
Energy: (W) [Joules], One watt is one Joule of energy transferred or dissipated in one second
- W = V2 * C/2: C =
capacitance in Farads
Energy Density: (by volume ~ Wh/l (by mass ~ Wh/kg)
- A unit in the category of Energy. It is also known as watt hours. Watt Hour (Wh) has a dimension of ML2T-2 where M is mass, L is length, and T is time. It can be converted to the corresponding standard SI unit J by multiplying its value by a factor of 3600.
Farad: (F) the SI unit of capacitance
- Electric capacitance.
- A Farad is the charge in Coulombs a capacitor will accept for the potential over it to change 1 volt. A Coulomb is 1 Ampere second.
- microfarads (μF or MFD), nanofarads (nF), or picofarads (pF), as one, millionths, billionths or trillionths of a farad.
Ferromagnetic:
- Of or characteristic of substances such as iron, nickel, or cobalt and various alloys that exhibit extremely high magnetic permeability, a characteristic saturation point, and magnetic hysteresis.
- Ferromagnetic materials
Ferromagnetism:
Ferromagnetism refers to the phenomenon by which ferromagnetic metals such as iron, nickel, cobalt and certain alloys become magnetized in a magnetic field and retain their magnetism when the field is removed.
Field Effect Transistor (FET):
- A transistor in which the output current is controlled by a variable electric field.
Field-Weakening:
- The introduction of resistance in series with the shunt wound field of a DC motor to reduce the voltage and current which weakens the strength of the magnetic field and thereby increases the motor speed. Is this really the definition that I want?
Flux: (Φ)
- Field Flux: (Φf) is produced by the coils and flows from + to -.
- Magnetic Flux:
(Φa) is produced by the coils and flows from N to S.
Flux Barrier:
Flux Vector:
Four Quadrant Operation:
Freewheeling Diode (Flyback Diode)(Snubber Diode)(Suppressor Diode)(Catch Diode):
A diode used to eliminate the sudden voltage spike seen across an inductive load when its supply voltage is suddenly reduced or removed.
Full-wave communication: (full-wave operation)
Gramme-type Winding:
Air gap.
Halbach Magnet Array:
Hall Effect Sensor:
- A Hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field density.
- Harmonic Distortion:
The presence of frequencies in the output of a device that are not present in the input signal, and are multiples of components of the input signal. Clipping is a common cause but other nonlinearities can also introduce harmonics.
- Harmonic Fields:
The sinusoidal Fourier components of a magnetic or other field confined to a finite region of space; their half-wavelengths are integral divisors of the length of the space in which the field is confined.
Heatsink:
Henry: (H)
Hertz: (Hz)
Homopolar Motor:
Hysteresis: [H] [magnet]
IGBT:
- See Insulated-gate bipolar transistor below
Impedance:
Inductance: (H) Henry the SI unit of inductance
Induction Motor: Squirrel Cage Induction Motor
- These motors are probably the simplest and most rugged of all electric motors. They consist of two basic electrical assemblies: the wound stator and the rotor assembly.
Inductor:
- An inductor or a reactor is a passive electrical component that can store energy in a magnetic field created by the electric current passing through it.
Insulated-gate bipolar transistor: (IGBT)
Inverter:
An electrical device that converts direct current (DC) to alternating current (AC), ie dc voltage into ac voltage.
- The inverter performs the opposite function from that of a rectifier.
Pulse Width Modulated Inverter
- There are several circuit topologies and control methods used to convert a dc input into a 3-phase ac output. A common circuit-topology is a voltage-source inverter .....
Ironless Core:
- The efficiency of ironless stator structures in permanent magnet motors is weaker than iron electrical machines but they can reach very high rotating speeds without the drawbacks of the eddy current effects.
Joule: (J)
Laminated Core: Laminated Iron Core:
- Laminated core eliminates eddy current due to alternating power source.
Lap Winding:
- A two-layer winding in which each coil is connected in series to the adjacent coil.
Left Hand Rule:
- If the left thumb points in the direction of electron current (purple arrow), the fingers of the left hand curl around the wire in the direction of the magnetic field. Mobile electrons are the actual moving charges in metals.
Magnet:
Magnet Bandage:
- A band (fiberglass and epoxy) used to hold the permanent magnets to the rotor.
Magnetic Arc:
Magnetic Field Intensity: [H]
Magnetic Field Strength: [H]
Magnetic Flux Density: [B]
- The amount of magnetic flux through a unit area taken perpendicular to the direction of the magnetic flux. Also called magnetic induction.
Magnet Leakage Flux:
- The magnet flux that jumps from one magnet to the next in the air gap without passing into the stator.
Magnetic Pitch:
Magnetic Reluctance:
Magnetic Skew:
Magnetic Slot Wedges:
Magnetic Span:
Magnetomotive Force [MMF]:
- The electromagnetic force that causes a magnetic flux to flow in a magnetic circuit.
Microcontroller:
Metal Oxide Semiconductor Field-Effect Transistor (MOSFET)
- Wikipedia and Maxim
- Also look at; - Insulated-gate bipolar transistor (IGBT)
- Also look at; - Bipolar Transistor
MOSFET:
- Metal-oxide-semiconductor field-effect
transistor.
Motor Constant: [Km]
- Motor Constant is the Peak Torque to the square root of the Input power at stall at ambient temperature. This ratio is useful during the initial selection of a motor because it indicates the ability of the motor to convert electrical power into torque.
- Km
- Km
Motor Losses:
- Core or Iron Losses
- Stator Losses:
- Rotor Losses:
- Friction and Winding Losses:
- Stray Load Losses:
Mutual Induction;
Mutual induction takes place when the magnetic field from current flowing through a circuit creates a changing magnetic flux in a nearby circuit.
See also; Self Induction
Neutral Point:
- The central junction of the three coil wires at the center of a Star connection in a motor.
Ohm: (Ω)
- The ohm is the Si unit of electrical impedance or, in the direct current case, electrical resistance. Ω = V / A
Outrunner Configuration:
- In the 'outrunner' configuration, the radial-relationship between the coils and magnets are reversed; the stator coils form the center (core) of the motor, while the permanent magnets spin on an overhanging rotor which surrounds the core. In all BLDC motors, the stator-coils are stationary.
Peak Input Power: [PP]
- Maximum power that can be delivered for even a short period of time. ???
- Input power at stall.
???
Peak Torque:
[KM]
- Maximum torque that can be delivered for even a short period of time.
Permalloy:
Permanent Magnet DC motor (PMDC):
- The field is created by permanent magnets.
- The higher the armature voltage, the faster the rotation. This relationship is linear to the motor's maximum speed.
Permeability: [magnet]
- The ability of a substance to acquire high magnetization in relatively weak magnetic fields.
Permeance:
- The inverse of reluctance. Permeance is a measure of the quantity of flux for a number of current-turns in magnetic circuit. A magnetic circuit almost acts as though the flux is 'conducted', therefore permeance is larger for large cross sections of a material and smaller for longer lengths. This concept is analogous to that of electrical conductance.
Poles:
- Refers to the number of magnetic poles arranged on the rotor of the brushless motor. Usually, the positive pole plus the negative pole are considered as being 2 poles. The two are considered as a 'pole pair'. Unlike an AC motor, the number of poles has no direct relationship to the base speed of the motor..
Pole Pairs: (p)
- The rotor is made of permanent magnet and can vary from two to ???? pole pairs with alternate North (N) and South (S) poles. One half the number of poles.
Pole Pitch:
- The angle between adjacent poles of the same polarity on the rotor of a Permanent Magnet motor. The pole pitch determines the full step angle of a Permanent Magnet motor.
Pole Shoe: ???
- Portion of a field pole facing the
armature of the machine; it may be separable from the body of the pole.
Polygon Connection:
A delta type of connection with more than 4 phases.
Power: (P)
- P = V x I.
where P is the electric power, V the potential difference, and I the electric current.
- P = I2 x R
and P = V2 / R. where R is the electrical resistance.
- Power Density:
Battery: ~
- Power Density (W/kg) indicates how much power a battery can deliver on demand.
- The amount of power available from a battery. It is expressed as the power available per unit volume or per unit weight (W/L or W/kg).
Motor ~ The output power per mass or volume.
Power Factor:
- Ratio of actual power to apparent power.
Power ~ Real, Reactive, and Apparent:
Precharge Resistor:
http://liionbms.com/php/precharge.php
Pulse Width Modulation: [PWM]
Pulse Frequency Modulation: [PFM]
Pulse Amplitude Modulation:
Quadrature:
The state of being separated in phase by 90° (/2 radians). Pertaining to the phase relationship between two periodic quantities varying with the same period, that is, with the same frequency or repetition rate, when the phase difference between them is one-quarter of their period.
Quadrature Axis: (Q-axis)
- Quadrature axis of a magnetomotive force is defined as that component of MMF that is directed along an axis in quadrature with the axis of the field poles.
Radial Flux Machine:
Reluctance:
- A measure of the opposition to magnetic flux, analogous to electric resistance.
Remanence: Remanent Magnetic Flux Density [Br]
- The magnetic flux density corresponding to zero magnetic field density.
Resistance: (R, Ω)
- Represents a measure of how much the material resists the flow of current.
- The SI unit of electrical resistance is the ohm, symbol Ω.
- R = V / I
Resistance - Terminal: [Rm]
- Terminal Resistance is the winding resistance measured between any 2 leads of the winding in either a delta or wye configuration at ambient temperature.
In Access database ~ Motor - Specifications.
Resistivity: (ρ) rho
Resistor:
- A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current passing through it in accordance with Ohm's law.
RMS Voltage:
(root mean square)
RPM Constant: (Kv):
This number is the motor voltage constant expressed in RPM/Volt. This indicates how fast the motor will turn for a given voltage.
The RPM constant of the motor. The number of revolutions per minute that the motor will turn when 1V (one volt) is applied with no load attached to the motor.
1000KV => 1000RPM per 1Volt; KV/rpm means how many rpm's you get with each volt of battery voltage under no load.
Converting from Star to Delta hookup, the RPM/volt value is multiplied by 1.73.
Converting from Delta to Star hookup, the RPM/volt value is multiplied by 0.578.
To size your ESC you use the Motor ratings. Not the Battery ratings. If your motor specifies 70A continuous, then you choose an ESC that can sustain that. I always allow for about 15% extra. Just to be save.
- http://www.flyelectric.com/ans.kv.html
- http://visforvoltage.org/
Rotor Spider:
- A set of radial arms that support the rotor core on the shaft. The use of a rotor spider also aids rotor cooling.
Rotor Yoke:
Salient Pole: (electromagnetism)
- A structure of magnetic material on which is mounted a field coil of a generator, motor, or similar device.
- Motors which depend on reluctance torque normally have "salient poles" - poles which stick out. This is to concentrate the flux into discrete angular sectors to maximizes and focus the alignment force between the fields.
Self Induction:
- Self-induction occurs because the changing magnetic field in a circuit induces an electromotive force in itself.
- See also; Mutual Induction;
Semens: (S)
Electrical conductance.
Servo Motor;
- Servo motors are used in closed loop control systems in which work is the control variable;
Shunt:
A conductor having low resistance in parallel with another device to divert a fraction of the current.
electrical shunt
Symbols:
Circuit Symbols
Sinewave:
Sinusoidal EMF Waveform:
Skin Effect:
- Skin effect is a term used when the electrons flowing through a copper wire tend to travel only in the outer circumference of the wire. The center of the wire is then just unwanted weight.
- Since the PWM will be at a high frequency also see
Litz Wire.
Slip:
The speed difference between the rotor and magnetic field, called slip, is normally referred to as a percentage of synchronous speed:
Slot Pitch:
- The center to center distance between two slots. But what is this on an axial stator?
Slotless Winding:
Airgap or slotless windings in PC-BDC
See paragraph on [PMMT p.258]
Slots:
- The laminated teeth in the stator about which the wire is coiled.
Soft Magnetic Composites:
- A magnetic material which is relatively easily magnetized or demagnetized.
- Shape capability and unique magnetic properties make components produced from SMC's good alternatives to lamination stack technology.
Speed - Frequency Relationship:
- f = n X p / 60
: f = cycles per second; n = revolutions per minute; p = pairs of poles.
Speed - No-load: [n0]
- The maximum speed of the motor under no load.
In Access database ~ Motor - Specifications.
Spider:
Squarewave:
- Squarewave machine (trapezoidal machines)
- Stall Torque:
- Maximum Continuous Stall Torque. The amount of torque produced at low to zero speed, which results in a 110 C rise in temperature. Based upon 20 C ambient temperature resulting in winding temperature of 130 C. [Nm]
- In Access database ~ Motor - Specifications.
Stall Torque:
xx.
Star Connection:
- A Y-shaped (Wye) connection in a three-phase load where one terminal of each phase is connected to a common point which is neutral. Also called Y-connection. Star is for higher torque output.
Stating Torque:
Stator:
- Core.
- Stacked laminates etc.
- Yoke. What is the difference?
Stator Tooth:
The laminate etc. about which the coil is wound?.
Stator Yoke:
- I think that this is the complete laminate unit. OR is it only the backing of the teeth?
Synchronous Motor:
- A synchronous electric motor is an AC motor distinguished by a rotor spinning with coils passing magnets at the same rate as the alternating current.
Tape Wound / Strip Wound:
Teeth:
xx
Telsa: (T)
Magnetic flux density
Terminal Resistance: (RM)
- Terminal Resistance is the winding resistance measured between any 2 leads of the winding in either a delta or wye configuration at ambient temperature.
Thermal Conductivity: (k)
Thermal Resistance: (RT)
- Thermal Resistance correlates winding temperature rise to the average power dissipated in the stator winding. Megaflux ~ The published value assumes that the motor is mounted to an aluminum heat sink of specific dimensions. Additional cooling from forced air, water jacketing, or increased heatsinking decreases the motor Thermal Resistance allowing higher power outputs than the published data.
Thermistor:
- One application is that of sensing the temperature of motor coils and conveying this information to the motor's controller.
Thyristor:
Tooth:
xx
Toroidal Winding: (Drum Type Winding)
Axial Flux motor. See [Source ~ AFPM p.35]
- Torque Sensitivity:
[KT] [V/Krmp]
Torque Constant: [KT] [lb-in/A]
- The ratio of the developed torque to the applied current for a specific winding.
KT is related to the BEMF Constant KB ~ from Megaflux
Torus Motor:
- The windings have the shapes of doughnuts and the laminate core does not have/require notches.
Transistor:
Transverse Flux Machine:
Trapezoidal EMF Waveform:
- xx
Turn:
- A single wrap of the wire around the pole of a stator.
- Number of turns per stator coil [Nc]
- Number of turns per phase [N]. The following one should be eliminated [Kw1]
Unipolar Switching: [Motor control]
- A drive that is capable of driving phase current in only one direction.
Variable Frequency Drive:
Varistor:
Volt: (V)
Watt: (W)
- The unit for measuring power. In physics terms, one watt is one Joule of energy transferred or dissipated in one second. Electrical power is calculated as: Watts = Volts x Amps x Power Factor.
Weber: (Wb)
Magnetic flux.
Winding:
- A winding is formed by one or more coils. A Coil is a conductor generally wrapped in a helicoidal form by certain number of turns.
- Winding Factor:
Pitch factor times Breadth factor.
Winding Configuration:
Winding Factor:
Wire:
- OTHER: Electrical - Motor - Stator - Wire
Wye Configuration, Star Connection (y):
- Go to Star Connection.
Outside Web Sites:
Glossary of Motor Terms ~ Rockwell Automation:
http://www.reliance.com/prodserv/motgen/b9652new/b9652.htm
Glossary related to motors:
http://powertecmotors.com/F2got.html
Glossary of Electrical Engineering Terms:
http://www.maxim-ic.com/glossary/
Electric Motor Definitions and Terminology;-
http://www.engineersedge.com/motors/motors_definitions.htm
Online Text book on Electric Circuits;
http://pergatory.mit.edu/2.007/Resources/databooks/lessons_pdf/AC.pdf#search=%22%22winding%20connection%22%20%224-phase%22%20-%22stepper%20motor%22%20-%22step%20motor%22%22
General Answers:
http://www.answers.com/
Glossary of Motor Terms
: http://www.empiremagnetics.com/glossary/glossary.htm
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Last Revised; Friday, August 21, 2010