UD53 User Guide
Issue code: 53nu3
D-2
Direction of rotation
Forward rotation is defined as follows:
Motor
Phase sequence: U V W
Resolver
COS modulation leads the SIN modulation (by 90°) (see Figure D–2)
Zero-position point
The resolver passes through its zero position when the following occur
(see Figure 4):
SIN output
• The modulation is at minimum
• The carrier waveform changes from being in anti-phase with the
excitation voltage on the primary to being in phase with the
excitation voltage on the primary
COS output
• The modulation is at maximum
• The carrier waveform is in phase with the excitation voltage on the
primary
Excitation
(primary)
SIN
secondary
COS
secondary
Carrier
in anti-phase
with excitation Carrier
in phase
with excitation
Carrier
in phase
with excitation
Zero position of resolver
Carrier
in phase
with excitation
Resolver
position
Figure D–2 Modulation and carrier-phase conditions around the zero
position of the resolver