Motor Phasing Process; Determining Phase/Hall Sequence - Aerotech BA10 SERIES User Manual

BA10/20/30 Series User's Manual
2.6.

Motor Phasing Process

When configuring the BA amplifier to run a brushless motor, the commutation signal
input connections (labeled HALL A, B, C on connector P1 pins 4, 16, and 17) are
necessary. These sequences and the generated output motor phase voltages (motor output
connections A, B, and C) are shown in Figure 2-9. The voltages generated are made under
the conditions of a positive signal placed at +INPUT with respect to -INPUT at control
signal input/output connector P1. A "0" for the given HALL input indicates zero voltage
or logic low, where a "1" indicates five volts or logic high.
If an Aerotech brushless motor is used with the BA amplifier, motor phase and
HALL connections can be easily determined by referring to the system
interconnection drawings in Figure 2-7, Figure 2-8, and Figure 2-9.

2.6.1. Determining Phase/Hall Sequence

For a motor with an unknown phase/hall sequence, a simple test can be performed on the
motor to determine the proper connections to the BA amplifier.
Before performing the following steps, ensure that the motor leads are completely
disconnected from the amplifier.
The tests outlined below do not require that the amplifier be turned on since Figure 2-
11 illustrates the generated output voltage of the amplifier relative to the input Hall
sequences.
The equipment needed for this test is a two-channel oscilloscope and three resistors
(typically 10 Kohm, 1/2 watt) wired in a "Wye" configuration.
Connect the ends of the three resistors to motor terminals A, B, C. Use one channel of the
oscilloscope to monitor motor terminal A with respect to the "Wye" neutral (eg., the
point where all three resistors are connected together). Turn the shaft of the motor CCW
and note the generated voltage. This voltage represents the "phase A to neutral" CEMF.
With the second oscilloscope probe, determine the Hall switch that is "in phase" with this
voltage. Similarly, phase B and C should be aligned with the other two Hall switches.
Refer to Figure 2-11 and note the generated output voltages of the amplifier relative to the
Hall sequences applied to HALL A, HALL B, and HALL C connections at connector
P1. For proper operation, the CEMF generated motor phase voltages should be aligned
to the amplifier's output generated voltage with the given Hall effect sequence shown in
Figure 2-11.
If the sequence of Hall signals relative to the generated motor voltage (e.g. motor CEMF)
is adhered to as illustrated in Figure 2-11; a positive (+) voltage signal applied to pin 8
(+INPUT) of connector P1 relative to pin 21 (-INPUT) of P1 or pin 19 (signal common)
of P1 will produce a CCW (e.g., a negative rotation) rotation of the motor shaft as viewed
from the front of the motor.
Version 1.6
Installation and Operation
Aerotech, Inc.
2-15