GMW-8288-2002.pdf
《GMW-8288-2002.pdf》由会员分享,可在线阅读,更多相关《GMW-8288-2002.pdf(21页珍藏版)》请在三一文库上搜索。
1、WORLDWIDE ENGINEERING STANDARDS General Specification Electrical/Electronic GMW8288 Thermal Evaluations of Electrical/Electronic Devices (Using Temperature Sensors And Infrared Thermographic Imaging Methods) Copyright June 2002 General Motors Corporation All Rights Reserved Originating Department: N
2、orth American Engineering Standards, Records and Documentation June 2002Page 1 of 21 TABLE OF CONTENTS 1INTRODUCTION2 1.1SCOPE. 2 1.2MISSION2 1.3DOCUMENT ORGANIZATION.3 2REFERENCES 3 2.1NORMATIVE.3 2.2GENERAL MOTORS DOCUMENTS3 2.3ORDER OF PRECEDENCE.3 3TEST OBJECTIVES, PREPARATION AND ACCEPTANCE CRI
3、TERIA4 3.1OBJECTIVES.4 3.2TEST PREPARATION - RESOURCES.5 3.2.1Calibration 5 3.2.2Parameter Definition and Tolerance.5 3.2.3Test Equipment and Orientation 5 3.2.3.1 Device Test Interface5 3.2.3.2 Device Mounting Orientation5 3.2.3.3 Operating Performance Measurements5 3.2.3.4 Thermal Test Chamber .5
4、3.2.3.5 Thermal Measurements Requirements.5 3.2.3.6 Thermal Sensors and Placement6 3.2.3.7 Attachment of Thermal Sensors6 3.2.4Electrical Loading Conditions examples are Dimmable Lamps and Pulse Width Modulated (PWM) solenoids. It is recommended that these loads should always be evaluated at the pow
5、er levels of the highest equivalent steady state current and voltage conditions for the device being evaluated. For example, a controlling device may dissipate maximum power and heat when operating an actuator in a low power state. However, the actuator will dissipate maximum power and heat when in
6、a full on state, which reduces the power and heat, dissipated in the controlling device. It is also recommended that transient conditions of less than 5 seconds (such as peak in rush or surge currents) should not be included in thermal evaluations. These parameters that have relevance to the electri
7、cal design of a circuit, have little thermal consequence, therefore efforts to simulate them during thermal evaluations are of little benefit. 5)Electric Motor Loads The electrical load of a motor increase as the mechanical load it drives increases. (Example wiper motors draw more current when wiper
8、 blades push heavy snow or operate dry, pump motors draw more current as they move thick cold fluids or pump against a head pressure). Therefore, test set ups which use unloaded motors for electrical performance evaluation are non-realistic and unacceptable for the thermal response evaluation of a m
9、otor or its control circuit. Thermal evaluations of electric motor circuits shall be performed using either a maximum loaded motor and/or a maxi- mum simulated load for worst-case stress evaluation. Loads that duplicate normal steady state voltage and current characteristics of a normally loaded mot
10、or are to be used for long-term durability evaluation purposes. Another aspect of motor operation that effects thermal performance is the high current load resulting from a stalled motor. This can produce a very hot thermal response for both the motor and an E/E control device. The recom- mended the
11、rmal evaluation for a stalled motor is 15 minutes of operation with the motor stalled at nominal voltage conditions. This should occur when the devices other inputs and outputs are operating in a moderate to heavily loaded state. Unless otherwise specified, it is recommended that only one stalled mo
12、tor load be evaluated at a time. -,-,- GMW8288GM WORLDWIDE ENGINEERING STANDARD Copyright June 2002 General Motors Corporation All Rights Reserved Page 8 of 21June 2002 Table 3.2 - Electrical Loading Conditions 6)Short Duration (SD) Tran- sients Loads Short duration, infrequent and non cyclical load
13、s such as: power door locks and windows, which last less than 30 sec- onds, typically have little thermal consequence. Therefore, efforts to incorporate them into accumulative thermal evaluations are of little benefit and are not recommended, unless otherwise specified in the devices CTS. 7)Temperat
14、ure Varying Loads Many loads, particularly resistive loads, vary with temperature. (Example: If a relay draws a maximum current of 200 ma when it is cold, this may be specified as the peak current to be provided to the relay by a solid state device. However, when hot, only 150 ma, 75 % of its cold l
15、oad is drawn. With a 14.5 V supply voltage, the voltage drop through the device is 2.0 V (12.5 V to the relays). Therefore, during hot conditions, 150 ma through the device produces 0.3 watts of dissipated heat. If the hot evaluation of the device were incorrectly performed (by using a 200 milli-amp
16、 load) then 0.4 watts (1/3 more power) would be produced. Such “over test“ errors could be multiplied by multiple outputs in a device. (Example - if the same error occurred for a device with 10 such relays driven by the device, the total power would be 4.0 watts instead of 3.0). This could drive a s
17、ignificant but non-relevant temperature increase, which could lead to inappropriate design changes and costs such as adding a heat sink to deal with the heat. The error of “under testing“ could also occur for devices that increase voltage drop or current flow with temperature. Also, because loads ma
18、y be located in a different part of a vehicle than its control device, it can not be assumed that the controller and the load are always experiencing the same environmental temperature. Therefore, a relevant ther- mal evaluation depends on selecting conditions appropriate to the ways electrical para
19、meters vary with the tempera- ture range of the load and/or the device. If temperature variation information is not defined it shall be deter- mined/developed by the GM Release Engineer and the Product Team and incorporated into the thermal evaluation). 3.3 Test Samples. The thermal evaluation proce
20、dures defined in this document are intended to be flexible and adaptable for use in early Product Development, Design Vali- dation, Product Validation, and Product Investiga- tion. Test samples used for early product development may range from breadboard or other forms of con- cept demonstrations mo
21、ck up, to application spe- cific alpha level prototypes Test samples used for design validation shall be production intent design and materials Test samples used for product validation shall be manufactured on production tooling, with production materials and processes. Test samples used for product
22、 investigations shall be from normal production lots. 3.3.1 Test Sample Conditioning. Not applicable. 3.4 Acceptance Criteria and Corrective Ac- tions Guidelines. The general evaluation criteria of Table 3.3 and/or any CTS defined criteria shall be applied to all of the Electrical, Functional and Th
23、ermal evaluations as applicable and appropriate to the DUT. For design features and requirements that do not meet the evaluation criteria of Table 3.3, and the CTS, additional investigations that are appropriate for determining suitable corrective actions shall be followed. Examples of effective add
24、itional investigations are: 1. Investigate methods to reduce the environ- mental temperatures the device must endure. Example: by relocating the device in a less stressful part of the vehicle, or using a heat shield and/or insulation, or by means of circula- tion cooler air around the device . . .et
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- GMW 8288 2002
链接地址:https://www.31doc.com/p-3765189.html