轴承加热器的软启动研究

范文编号:ZD946    范文字数:13281,页数:33

摘 要
 通常对中小容量的电机，变压器等电器均采用直接启动,即电器在额定电压下直接启动。例如电器直接启动时, 启动电流大, 可达额定电流的5～7 倍, 造成电动机绕组因启动电流过大引起过热,从而加速绝缘老化,会造成供电网络电压降低过大等缺点。开关电源由于具有效率高,输出电流大,静态电流小,体积小等优点而在手持式设备和便携式产品中得到广泛应用,成为了电源ASIC的主力军而典型的开关电源在启动过程中,容易产生浪涌电流并引起输出电压过冲,可能对电子系统造成损伤,因此需要软启动电路。
 本文主要介绍了几种软启动电路的特点和功能，为了配合轴承加热器，选取了在开关电路中加上软启动电路，为了使加热器平滑的启动和免维护，设计这个带软启动的负载开关来实现保护节能控制。

关键词：轴承加热器  软启动  负载开关

Abstract
 Usually small and medium-sized Motors, transformers and other electrical appliances are used directly to start, that is motor rated voltage in the direct start. Directly activate the AC motor, the starting current, and rated current up to 5 ~ 7 times, resulting in motor windings due to excessive starting current over-heated, thus speeding up the aging of insulation, this will result in electricity supply networks, Result in reduced power supply network voltage is too large, such as the shortcomings. Switching power supply because of its high efficiency, large output current, static current, the advantages of small size in the hand-held devices and portable products are widely used, has become the main force of the AS IC power and a typical switching power supply in the boot process, easily lead to surge current and cause the output voltage overshoot may cause damage to electronic systems, so the need for soft-start circuit.   In this paper, several soft-start circuit of the features and functionality, in line with the Bearing processing, select a switch circuit with soft-start circuit, in order to enable a smooth start-up heater and maintenance-free design with soft-start the load switch to achieve the protection of energy-saving control.
 
Keywords：Bearing InductionHeater ,soft-start , load switch

目  录
摘 要 I
Abstract II
1  绪论 1
1.1背景 1
1.2选题的意义 2
2  软启动技术的基本知识 3
2.1 软启动器 3
2.2 软启动的启动方式 3
 2.3 软启动的特点 4
2.4 电动机软启动技术的应用 4
2.5 常用的软启动电路 5
2.5.1 采用功率热敏电阻电路 5
2.5.2 采用SCR-R电路 6
2.5.3 具有断电检测的SCR-R电路 6
2.5.4 继电器K1与电阻R构成的电路 7
2.5.5 采用定时触发器的继电器与限流电阻的电路 7
2.5.6 过零触发的光耦可控硅与双向可控硅构成的电路 8
3 新型软启动电路  9
3.1 新型可内置软启动电路 9
3.1.1 软启动原理 9
3.1.2 新型软启动电路分析 9
3.2 固体软启动开关控制 11
3.2.1 电路结构 11
3.2.2 工作原理 12
4 轴承加热器  14
4.1 轴承加热器 14
4.2 轴承加热器的原理 14
4.3 简易轴承加热器的制作 14
4.3.1 简易轴承加热器的结构和工作原理 14
4.3.2 加热温度的确定 15
4.3.3 轴承加热与安装 16
5 轴承加热器的软启动电路  17
5.1开关导通的冲击电流 17
5.2 新型负载开关的结构 18
5.2.1 输入输出电路 19
5.2.2 负载开关基本电路 19
5.2.3 电平转移电路 20
5.2.4 软启动电路 21
5.2.5 带软启动的负载开关电路 22
5.2.6 电路的特点 22
5.3有关元器件的选择在电路中主要选择的元器件 23
5.4新型软启动元器件 24
6  结束语 26
致谢 27
参考文献 28
附录1 29

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