Toshiba 18 - 1250 A Benutzerhandbuch

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TE Series        
          Digital Solid State Soft Starters   18 – 1250A 
20 
4.2.6   PTC Thermistor Input 
The TE Series starter is provided with input terminals for connecting a 
PTC (Positive Temperature Coefficient) Thermistor that may be 
imbedded in the motor. These are specialized resistors imbedded in 
some motor windings that increase resistance as the temperature 
increases. When the TE Series detects that the PTC input resistance is 
too high, it initiates a PTC trip, and displays it on the readout as  
[ PTc ]. This is independent of the Thermal Register overload current 
protection and provides supplemental protection for high motor ambient 
temperature applications. Terminals for this input are provided with a 
factory jumper that must be removed if the PTC input is used. These 
terminals are located on TB1, Terminals 9 and 10.  
 
PTC resistors are also found in other devices such as bearings, air 
receivers, oil or coolant reservoirs and air discharge systems that may 
require shutdown of the motor. 
 
PTC Resistor Values: 
Resistance must be greater than or equal to 750 
Ω at 25ºC. If multiple 
resistors are used in the motor, the sum of all resistors in series must 
equal or exceed this value. 
 
 
ƒ  4.2.6.a  
External Over Load Relay Connection 
If an external Over Load Relay (OLR) is used (see Section 3.1.3.c 
and Appendix 5), connect the NC aux. contact of the OLR to the 
PTC input after removing the jumper. When the external OLR trips, 
the contact will open, opening the resistance input to the PTC circuit 
(the resistance goes to infinity). This indicates an immediate Over 
Load to the starter, which trips and displays it on the readout as  
ƒ  [ PTc ] to differentiate from the internal Thermal Over Load trip. If 
multiple OLRs are used, i.e. multiple motors controlled by the same 
TE Series starter, simply wire the Aux Contacts in series as shown 
in Figure 4.2.6.a. See Appendix 5 for additional information. 
 
ƒ  NOTE: 
An Emergency Stop Push Button or any other field device may be 
wired to the PTC input using NC contacts. When the contacts open, 
the starter will detect it as a PTC trip. Even if a PTC is used in the 
motor, field devices can still be added as long as the total circuit 
resistance is not exceeded. 
ƒ  This feature is especially useful when using Decel Control because 
it will immediately shut off power to the motor even if Decel is 
active. If used this way, instruct the users as to the trip indication 
issues (i.e. the display will show [ PTc ] and the Overload LED will 
be on). 
 
+
N C
JOG
RAMP2
PTC
OPTO
Figure 4.2.6:
 PTC Resistor Connection
TB-1
PTC Resistor in Motor
9       10
**
** Remove  factory jumper
    from Te rminals 9 and 10
N C
JOG
RAMP2
PTC
OPTO
Figure 4.2.6.a:
 External Overload Relay(s)
and/or E-Stop PB Connection
TB-1
External OL Relays
OLR 1         OLR 2
9       10
Optional
Emergency Stop PB
**
** Remove factory jumper
    from Terminals 9 and 10