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There are many companies that make Permanent Magnet Brush less Motors and all have there own variety of variables they use to for the analyse of the motor. I reviewed many of these sites and took the variables that made the most sense and came up with the set in Table 1.0. For simplicity an in order to help present the analytical sections of this TDA we are going to present the following naming convention along with a set of symbols that define specific parameters of the PMB DC motor. We will reference these parameters throughout the analysis. The analysis that we will present will be in two states, Steady State or Static performance and Commutating or Dynamic performance. Our main objective is to use the data collected for proof of concept in order to develop a reliable test criteria for the Hybrid Power Modules Test System as defined in the Bridge Test System TDA. Characterising a motor However, would require the addition of a dynamometer along with a few other parameters. As stated previously we will cover this in another TDA.
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The applications of Faraday's Law states
that an EMF
will be generated due to the magnetic field (Flux) and the field windings
passing in proximity to each other. This EMF is the Motor Voltage
Generator Constant
Keeping the terms in
the proper domains, the conversion to electrical rotation radians/seconds (Rotational
Position per Second) is also required. From the previous page,the Electrical
revolutions with relation to the mechanical revolutions is defined
as
The 3Ø Motor Generator equations that define
the EMF generated Line to Line Voltage equation set for 3 wire DELTA system, Line to Line
Voltage equation set for 4 wire WYE system, Line to Neutral
Generator Voltage developed at 100 RPM
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times the coil voltage. In the Delta configuration the coil voltages are
equal and the line currents are 
times the line current. The equation sets derived here are for the
purpose of characterizing system block functions.
The actual losses within the motor are not covered
here except where they have direct connections to
the equation set. The manufacturing efficiency and
design parameters of the motor are usually supplied
by the manufacture. We will discuss motor efficiency
and characterizing in a later article. 
and for a typical 6 pole motor is in the range
of 1 to 6 volts / 1000 RPM, where the average is around 2.5 volts/1000
RPM. The motor manufacturer will give this constant in the motor
specifications. The contributing factors of this constant are the
magnetic field strength, the coil size and the number poles. Since
this is in a rotating environment, then in order to use this in our analysis we have to transform
this to an angular or polar domain, hence; Volts /Radians/Seconds relating
to electrical revolutions. Converting this to seconds is a preference
and does not matter in the final analysis as long as the labels
are in domain order. First rule of analysis if the labels do not
make sense neither will the results. 
Hence: 
. Therefore the Electrical Radian/Seconds to mechanical rotation is defined
as: 
Hence: 
This now satisfies the domain changes and labeling.
, 
, 
and
Line to Neutral 
, 
using phase ab as the 0º reference are as follows. Plotting
these equations gives us a better perspective of the voltage levels of
the two systems. For those who want to research this further,
these equations are derived from applications of poly-phase systems
and phasor geometry.
