Title:
【発明の名称】連続するストリップを乾燥させるための加熱装置における加熱素子の出力を調整する回路装置
Document Type and Number:
Japanese Patent JPH09501523
Kind Code:
A
Abstract:
The invention concerns a circuit assembly (100) for controlling the output of the heating element (28) of a heater for drying a continuous strip of material, the output being controlled as a function of a parameter which is dependent on the moisture content of the part of the strip of material heated by the heater and which is measured in situ by a signal-generating sensor. The circuit assembly (100) includes a pulse-width modulator (5) which operates at a carrier frequency of 1 kHz and whose timing ratio is varied, as a function of the value of the parameter, between 0 and 90 %. The pulse-width modulator (5) is used to control an electronic power switch (29) designed as a npn insulated-gate bipolar transistor (IGBT) and connected into a power circuit (60). The firing period of the IGBT is determined directly by the pulse-modulated signal. The heating element (28) is operated by d.c. generated by a six-pole bridge circuit (25) connected up to the phases R, S and T of the three-phase mains supply. The circuit assembly (100) further includes a starter circuit (11), which controls the current to the cold heating element (28) on starting, plus a monitoring circuit (14) which controls the functioning of the circuit assembly (100), in particular switching the IGBT (29) off when the power current (I) exceeds the maximum admissible level.
Inventors:
Vivekens, Werner
Wrocka, Bernhard
Krieger, Detreff
Wrocka, Bernhard
Krieger, Detreff
Application Number:
JP50428394A
Publication Date:
February 10, 1997
Filing Date:
July 12, 1994
Export Citation:
Assignee:
Krieger Gesell Shaft Mitt Beschlenktel Haftung Und Company Comandito Gesell Shaft
International Classes:
G05D22/00; D21F5/06; D21F5/16; F26B23/04; F26B25/22; G05D22/02; (IPC1-7): G05D22/00
Attorney, Agent or Firm:
Toshio Yano (3 outside)