• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
Wiring precautions
Transient operating periods

TM-5-3895-374-24-1 Paving Machine Bituminous Material: Crawler Mounted Diesel Engine Driven Manual
Page Navigation
  163    164    165    166    167  168  169    170    171    172    173  
TM 5-3895-374-24-1 Recommendations for use of the motor/speed controller combination Thermal protection Indirect protection of the motor is incorporated in the speed controller, taking into account of the motor - the current absorbed by the motor, - the motor speed (ventilation), - an ambient air temperature of 40?C. See tripping curves on the left. For adjusting And monitoring of the thermal state of the motor, see p. 49. To provide direct thermal protection, use PTC thermistor probes embedded in the motor windings, associated with an LT2-S protection relay, for operation in severe ambient conditions : - high ambient temperature (0 > 40°C), - risk of cooling fins clogging, - insufficient ventilation Intermittent duty The amount of starting and braking is limited by the value of the overloads, their duration, as well as the load during normal running and the motor cooling possibilities. On intermittent duty, the current which causes the motor and speed controller to overheat appears as follows: IM: overload current In: rated current Im normal runnning current The following curves can be used to determine the ratio between the overload duration and the operating time at 0,8 of the rated current at rated speed EXAMPLE following an overload of 1,3 in for 10 seconds, it would require 20 seconds at 0,8 in to return to the previous thermal state If the normal running speed is lower than the rated speed, time t2 will be longer (page 3-181)







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.