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The Challenge:
To design and develop a Single Test Bench for in-line functional testing of different types of commercially used Power Tools.
The Solution:
The test bench is implemented by controlling an eddy current dynamometer through Analog Output to create the load on the power tool and acquire various parameters like current, voltage, vibration, rpm, temperature & sound using necessary sensors, National Instruments’ Signal Conditioning and DAQ devices.
We selected LabVIEW to implement this application. The Signal conditioning modules were NI SCXI-1530 as the front end for vibration and noise, NI SCXI 1102 for conditioning temperature data and SCXI-1125 to measure the voltage (230 VAC) and current drawn by the tool. A Computer having NI PCI 6527 is installed on it, controls the sequence of operations. The operator interfaces are created using LabVIEW graphical support. The report generation Toolkit and SQL toolkit are used for creating custom reports.
Introduction:
The functional test is carried out in two parts, the first without applying any load to the tool and the second by applying load on to the tool.
The No-load test when executed measures the Starting Current, Running current, rated voltage, No-load power, Vibration, Noise, Speed and temperature of the tool when no load is applied to it.
The Load test is carried by first running the tool for an user specified time without load and then gradually applying the specified torque through the Eddy current based Dynamometer and measure Running current, Power, voltage, Vibration, Noise, Speed, torque and change in temperature on the housing of the tool.
Magtrol’s WB series eddy current Dynamometer WB-20, which is capable of generating 20 Nm Torque is used as the load. The dynamometer is connected to the corresponding Tool through a coupler and the set torque is gradually applied to the tool.
System Configurations:
There are five different types of Tools that have to be tested – Drill Gun, Angle Grinder, Mini-Angle Grinder, Marble Cutter. Each type of tool is mounted on a different fixture. Some of the sensors like Thermocouples and Accelerometer are attached to the fixture in order to make necessary contact to the Power Tool. Other sensors like Hall Effect Sensor (LEM Make), Microphone, Infrared Temperature sensor, Proximity sensor and the Dynamometer are common to the Bench.
The torque is generated using Magtrols WB series eddy current dynamometer which is controlled by the Analog Output of the NI PCI 6035 E DAQ card. The vibration is measured using B&K make accelerometer and Sound level is measured using B&K make falcon microphone. National Instruments’ signal conditioning modules SCXI-1530 is used for signal conditioning of the ICP based accelerometer and microphone.
While executing load test, the Power Tool’s temperature will rise, this increase in temperature is measured using T- Type Thermocouples mounted onto the fixtures. The speed sensor and LVDT (part of the Dynamometer) gives the corresponding values of speed of the tool and the torque applied to it. These data are acquired and logged on to MS Access database. The emergency alarms are read using PCI 6527 DIO card and shutdowns the bench. In case of any alarm.
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