YASKAWA A1000 Technical Manual page 270

5.8 L: Protection Functions
Figure 5.90
Operation time (minutes)
10
7
3
1
0.4
0.1
0
Figure 5.90 Protection Operation Time for General Purpose Motors at the Rated Output Frequency

Motor Protection Using a Positive Temperature Coefficient (PTC)
A motor PTC can be connected to an analog input of the drive. This input is used by 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 stop method determined in L1-04.
Connect the PTC between terminals AC and A3 and set jumper S4 on the terminal board to "PTC" like shown in
Figure 5.91. Set parameter H3-05 to 0 and parameter H3-06 to E.
Figure 5.91
The PTC must have the following characteristics for one motor phase. The drives motor overload detection expects 3 of
these PTCs to be connected in series.
Figure 5.92
Overheat detection using a PTC can be set up by parameters L1-03, L1-04, and L1-05 as explained below.
270
100 150 200
Multi-function input
DIP Switch S4
PTC
AI
A3 (0-10 V)
PTC
thermistor
AC
Figure 5.91 Connection of a Motor PTC
Tr - 5K (oH3 Alarm Level)
Figure 5.92 Motor PTC Characteristics
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
Cold start (Characteristics when an overload occurs
at a complete stop)
Hot start (Characteristics when an overload occurs
during continuous operation at 100%)
Motor current (%)
E2-01 = 100% motor current
Drive
MA
Fault output
MB
MC
M1
M2
Multi-function
M3
digital outputs
M4
M5
M6
Tr'
Tr + 5K (oH4 Fault Level)