During normal operation, motor overload protection operates in the area between a cold start and a hot start.
• Cold start: Motor protection operation time in response to an overload situation that was suddenly reached when starting a
stationary motor.
• Hot start: Motor protection operation time in response to an overload situation that occurred during sustained operation at
rated current.
Operation time (minutes)
Cold start
Hot start
Motor current (%)
E2-01 = 100% motor current
10
7
3
1
0.4
0.1
0
100
150
200
Figure i.56 Motor Protection Operation Time
n
Motor Protection Using a Positive Temperature Coefficient (PTC) Thermistor
Connect a motor PTC to an analog input of the drive for motor overheat protection.
When the PTC input signal reaches the motor overheat alarm level, an oH3 alarm will be triggered and the drive will continue
operation as selected in L1-03. When the PTC input signal reaches the overheat fault level, an oH4 fault will be triggered, a
fault signal will be output, and the drive will stop the motor using the stopping method determined in L1-04.
Figure i.57
shows a PTC connection example for analog input A2. When using analog input A2, be sure to set Jumper S1 on
the control board for voltage input when using this function.
Drive
+V
(+10.5V, 20 mA)
Branch
resistor
12 k
PTC
thermistor
A2 (0-10 V)
AC
Jumper S1
Terminal A1/A2
Voltage/Current
Selection
V
I
A2
A1
Figure i.57 Connection of a Motor PTC
The PTC must exhibit the characteristics shown in
Figure i.58
for one motor phase. The motor overload protection of the
drive expects 3 of these PTCs to be connected in a series.
i.5 Start-Up Programming and Operation
YASKAWA ELECTRIC TOEP C710616 54A YASKAWA AC Drive - Z1000 Quick Start Guide
59
Summary of Contents for Z1000 CIMR-ZU*A Series
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