BellMega BM-510 Operation Manual Ver: 1.0 Rev: 1
CONTENTS Page Description 1 Operation 2 Safety 2 Charging 3 Service / Calibration 3 Specifications 4
Description The BellMega is a continuity tester for point to point wiring verification and includes Earth Leakage Detection of the wiring being tested. The leakage resistance is detected within 250ms @ 110M Ohms. The high voltage DC source is regulated to provide a stable reference for insulation breakdown resistance detection. The earth leakage threshold is detected using the voltage divider principal. A regulated high voltage is applied to two known HV metal film resistors and a variable resistor is used to calibrate the threshold of detection as a function of time and leakage resistance. i.e.: 110M Ohms will trip the alarm in approx 200Ms, 10M Ohms will trip the alarm in approx 20Ms. The important point is that this is shorter than the response of the bell tone. As any leakage resistance <110M Ohms will trip the unit, the high voltage drop - 371v @ 0.909M Ohms is of no relevance because the detection of the leakage resistance is a function of the regulated high-voltage supply (1%) and calibrated internal resistance. The BellMega includes battery state monitoring via a green / red led on the front panel. When the led turns red (<10.4v) continuously it is time to charge the battery. A low voltage (<9.8v) disables the continuity test tone, ensuring the high voltage DC is still valid and the circuit is functioning predictably during a period of low battery supply. For maximum battery life, the unit should only be recharged when the led turns red. The BellMega has front panel test points to verify that the unit is operating within specifications before testing any wiring. Use the black lead -> test points for checking operation. (See fig 1) The high voltage can be tested using a 10M Ohms Digital multimeter only, (i.e. Fluke 87), measure the voltage between the black and green terminals, the result should be 520v + 10v/-5v. The 10mA constant current source can be tested by connecting an ammeter to the black and red terminals. A hi/low sound level is provided to accommodate different testing environments. There are three fuses internally, AC/DC in, Probes and DC-DC Converter, for protection against excess current faults. These fuses are not user replaceable. Copyright 2005, MRD Rail Technologies Pty Ltd, All Rights Reserved Page 1
Operation 1 When the unit is first switched on, the insulation alarm may sound. Press reset to clear. The Battery LED should be green and the neon indicator near the Earth terminal should be on. Note: The battery status LED is only valid during use and is not a fully charged indicator for charging. 2 Check the BellMega unit at the start of the bell testing by using the front panel test points. The bell tone should sound only for the 8R test. The Insulation alarm tone will latch on only for the 80M and 100M test. Press the reset to cancel the alarm tone. If any of these tests fail, do not use as the unit may require service or calibration. 3 If the unit is in calibration and passes all tests, connect the earth lead of the BellMega to the earth bus of the equipment to be tested. Ensure all equipment earths are terminated. The red and black leads are for the continuity (bell) testing. Any earth leakage <110M Ohms will trip the earth alarm (low tone) and disable the bell tone. Press the reset to cancel the alarm and investigate the source of the earth leakage. When the battery LED turns red it is time to charge the battery, continuity function will disable if the unit is used to further discharge the battery. 4 If the wiring being tested is live, the continuity tone will be disabled and the live circuit LED on the front panel will light, if the voltage is greater than 23v. 5 During extreme humidity environment and low air circulation, the earth leakage alarm will trip. This is mostly caused by old test leads and surface resistivity on equipment terminals. This can be remedied by replacing test leads with new 1kv PVC 24/.020 wire. Silicone test leads can be used, but are usually not suitable due to the reduced mechanical strength. Improving air circulation by using a fan will also reduce false tripping due to surface condensation. The unit can also be re-calibrated and labeled accordingly to suit requirements. Safety The BellMega is a HIGH VOLTAGE power supply and should be treated with care and respect. Do not touch the probe tips and earth / case at the same time. The +high voltage (530v) has approximately 200k Ohms series resistance between EARTH terminal / case and probes. The EARTH terminal is connected to the BellMega CASE. Only Authorised and Qualified personnel to open the case. Disconnect all electronic equipment from wiring before bell testing. Ensure no flammable gases or other flammable substances are present when bell testing. Do not use the BellMega if it gets wet. Copyright 2005, MRD Rail Technologies Pty Ltd, All Rights Reserved Page 2
Charging Important: Recharge battery as soon as possible after use and especially before the unit is to be stored or unused. The BellMega uses a 1.3ah sealed Lead Acid battery, it is not necessary to wait for complete discharge before recharging. The charger in the BellMega is a constant voltage / current limited type and requires a suitable plug pack power supply. The charging can be left on indefinitely as the battery will be floated at 13.6v. For best results the unit should be charged for 4-5 hours. Always fully charge the battery if unused. The unit can be operated while being charged, only if the supply is isolated from the mains earth and fully insulated power leads are used. After long term storage (6-12 months), the battery capacity is initially reduced, normal capacity will return with 2-3 charge / discharge cycles. Service / Calibration Important: The case may be opened only by authorised service personnel. Calibration can only be guaranteed if the unit remains sealed from the previous calibration and is re-calibrated within due date specified. Danger: The 530v present within the case has lethal current capability due to its low impedance and regulated characteristic. Warning: The case is connected to the +530v DC via a 100k resistor, this is EARTH. Remove jumper from J1 before connecting test equipment. This will disconnect the earth connection from the case. This is because testing and calibration are done with reference to battery 0v. Calibration must be performed by authorised personnel or approved calibration lab only, using calibrated, traceable test equipment to ISO/IEC 17025. Copyright 2005, MRD Rail Technologies Pty Ltd, All Rights Reserved Page 3
Operating Specifications Specification: REV C Insulation leakage trip Insulation leakage trip response time Insulation voltage High voltage supply Insulation short circuit current High voltage drop at terminals Continuity threshold Continuity constant current Continuity applied voltage Continuity response time Live circuit tolerance Live circuit LED operates at.. Operating supply range (battery) Low battery warning LED at.. Low battery disable Operating current (battery) Operation time (fully charged battery) Operation time (using plug pack) Plug pack type Battery Charge time Insulation sound frequency lo Continuity sound frequency hi Switch mode cycle frequency 110M ohm 200 ms @ 100M / 100pf 520v dc +10/-5% @ 10M (note 1) 530v dc regulated 1% 1.5mA max 506v @ 5M ohm. (note 1) 371v @ 0.909M ohm. (note 1) 10 ohm 10mA +/- 1mA 11v dc+/- 2v (red = +) 400ms +/- 100ms 250v ac/dc (350v peak) 25v ac/dc 9.6 13.6v 10.4v +/- 0.2v 9.4v 10.4v 125mA 7 hours (approx.) Indefinitely 15 18v ac/dc @ 600mA(min) EARTH ISOLATED!!!!!!! LCR12V1.3P 12V 1.3AH/20hr 3.9 hours min. 1.7khz +/- 100hz 2.2khz +/- 100hz 40 70khz (factory set) Copyright 2005, MRD Rail Technologies Pty Ltd, All Rights Reserved Page 4