Pg Motor Drive Circuit - Epson DFX-8500 Service Manual

2.3.7 PG Motor Drive Circuit

Figure 2-25 shows a block diagram of the PG motor drive circuit, and Table 2-11 provides PG motor
specifications.
The PG motor is a stepping motor. The motor phase switching signals are output from the E05B36 ports
PGA to PGD. The motor common voltage (PGCOM) alternates between drive mode (+37 VDC) and hold
mode (+5 VDC) using the PG H/R signal of E05B36. The phase driver circuit is made by discrete transistors
Q12 to Q15.
The phase A output pulse from the platen gap encoder (ENCA) is input to port ENCA of E05B36 and the
phase B output pulse from the platen gap encoder (ENCB) is input to port ENCB of E05B36. The E05B36
counts these pulses using the internal counter and determines the amount and direction of motor rotation.
Specification
Form
Supply Voltage
Internal Coil Resistance
Current Consumption
Frequency
Driving Method
Rev. B
Table 2-11. PG Motor Specifications
Description
4-phase, 48-pole, PM pulse motor
37 VDC (applied to the drive circuit)
250 + 18 ohms per phase at 25
Driving: 0.20 A (average)
Holding: 0.02 A + 5 mA
285 pps
Constant voltage driving, 2-2 phase drive
Figure 2-25. PG Motor Drive Circuit Block Diagram
OPERATING PRINCIPLES
o
C
2-31