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Q. What documentation is there available to help me use this unit?
A. We have a series of documents to help you: Application Handbook AN105 Module Configuration Rule Guide, included in AN105UL report CB report Mechanical outline files to download Datasheets Configuration Ordering Sheet, for simple custom configurations.
Q. Can I use contact closure for inhibiting/enabling?
A. Yes. Options 06 & 07 include a SELV bias voltage (5V @ 50mA). Application Handbook AN105 decribes how this facilitates global inhibiting/enabling by means of simple contact closure.
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Q. Can I series connect modules?
A. Yes you can. There are a number of things to be aware of: Outputs are rated SELV (Safety Extra Low Voltage), that is that output voltages are guaranteed to less than 60 volts. Stacking 3 by 24-volt output units is over SELV. So be aware and take appropriate precautions. It is good practice to stack modules with a similar output current limits, so that in the case of short circuit the outputs collapse together, You should connect the exterior sense connections to the load either locally or at point of use, and the interior connections using U connectors to the local sense. You can specify special links for seriesing modules on our configuration chart : we supply special Z link connection bars (part number 61070) for series connection to reduce wiring complexity. These can be fitted at the factory (see Configuration Ordering Sheet MD-3GCONFIG-05/00)
Q. How do I parallel modules?
A. Simply connect the outputs together using our paralleling bars - there are some things to be aware of: Max continuous output current should be specified at 90% of the sum of the output currents. Only parallel modules of the same type Follow the paralleling set-up procedure below Derate each module by 10%. Use local sensing links Adjust the setting on each output module separately, but to the same value You can specify special links for paralleling modules on our configuration chart: we supply special I link connection bars (part number 61069) for parallel connection to reduce wiring complexity. These can be fitted at the factory (see Configuration Ordering Sheet) Simple Paralleling does not force current sharing, but is sufficient for most applications.
Q. How can I force current sharing between modules and units?
A. This may be achieved by use of Excelsys proprietary "wireless" current sharing as follows: Only parallel modules of the same type Derate each module by 10% Use negative sensing only (either local or remote). Do not use positive sensing Adjust the setting on each output module separately, but to the same value For best performance, ensure symmetry in power cabling Take power from the +V terminal only Measure the voltage between the +S terminals on each output and trim the adjustment potentiometer on one module to null (=zero) this measured level. (typically, a voltage of 100 mV will be measured and try to adjust to less than 5 mV). This procedure forces a deliberate degrading of the load regulation to around 0.5%, and will ensure load sharing to within approximately 10%.
Q. How can I inhibit or sequence an output?
A. You can do this 2 ways. Firstly, a single output can be inhibited by applying a voltage of >3volts (2mA load) to pin 3 of J3 on an individual module. Applying this voltage sequentially to different output modules, a unit can be sequenced to any combination of output timings.Secondly, all outputs can be inhibited through an opto isolated photo-diode requiring 5mA of external current (Global Inhibit / Enable) connected between pins 3 (anode) and 4 (cathode) on connector J1. It is good practice to provide reverse voltage protection to the opto-coupler diode by means of an external inverse diode. This can be driven from a 5 volt / 1 K ohm source. See another question for inhibiting/enabling using contact closure.
Q. How do I connect up remote sense?
A. Units are shipped with a special U link (part number 362D010) that connects the sense pins to power pins as standard for all single output modules. (You can specify non-connection using our configuration-ordering sheet MD-3GCONFIG-05/00). If you wish to remote sense then do not forget to remove this. It is good practice to use twisted pair for remote sensing, and to decouple using a 100ohn series resistor and a 22µF Capacitor. It is not good practice to try to draw your load current though the sense wires ... we've seen it, believe me! Remote sensing will adjust for up to .25 Volts .
Q. My output voltage is sagging. Why?
A. A common fault is that the local sensing U link is not tightened! Check it!
Q. Where is the output voltage potentiometer adjustment?
A. This is located to the top right of the positive power pin of the output module. Be careful when adjusting not to short an output terminal to ground.
Q. When I connect a 4 slot up to an electronic load, the voltage falls and the unit buzzes. What's going on? I have the sense leads connected up and all the wiring in place.
A. Firstly, check the wiring. Sense leads are very vulnerable to noise pick up. Don't forget that the units output is directly modulated by the voltage on the sense wire. Try a 100 Ohms in series with the sense terminal and a 22 µF cap between the load and the sense. Further, it is good practice if the sense wires are loosely twisted ( 1 turn per cm is about right) to reduce noise. Secondly, check the load: is it set correctly? Are you trying to draw too much current and entering into current limit? If these initial checks fail, then call us: We'll be glad to help.
Q. How do I calculate the power rating of an input module?
A. The 3GEN Series is designed to provide maximum output power at nominal output voltages. We calculate the power output of a unit by using the nominal output voltage (not the set voltage) multiplied by the maximum continuous current you plan to draw. These should be summed for all modules: the total power should not exceed the maximum power of the input module selected. Use the module's full current (not derated) capacity for output power calculations even when using multiple modules of the same type in parallel.Power derating should be applied to input modules as follows:For temperature: 2.5 Degrees C per degree above 50 degrees C Ambient operating temperature For Line Voltage: derate input module D to 1000W peak for 10 seconds maximum , or 800 watts average power for input voltages less than 180 volts. This restriction only applies to input module D, there is no need to derate input modules B and C
Q. How can I get 1000 watts of output power in the 110 Volt US environment?
A. You can get 1000 watts of output power by connecting across 2 phases of a 3 phase supply (normally 208 volts).
Q. How much space do I need to allow for air intake and exhaust?
A. Nominally 30mm on either end is sufficient.
Q. Is their any restriction of mounting orientation?
A. No. The unit will operate quite happily in any mounting orientation
Q. What life testing has been carried out on the unit?
A. We have carried out functional electrical tests on our 4 slot units to 150G random, 3 axis vibration, in a temperature whilst ramping temperatures from -60 degrees C to +100 degrees C, ramping at 70 degrees C per minute, to provide highly accelerated life testing (HALT). The unit operated satisfactorily, albeit with degraded regulation performance at temperatures below -20 degrees C. In addition MTBF figures calculated from life testing carried out by Excelsys may be found in our application handbook AN105.
Q. How can I certify my equipment with your power supply?
A. We supply a certified component that carries CE and UL certification if used in accordance with the installation instructions. CB and UL reports can be requested for aiding your submission to your certification body. Providing you are using the unit in accordance with the installation rules, then this process should be straightforward.
Q. How do I fuse my equipment?
A. This is a class one power unit and must be earthed by a secure connection to ground. If in the end use equipment, the incoming mains cable earth wire connects directly to the "GND" connection on the 3GEN unit without being interrupted or junctioned on its way to that connection, then this connection forms the main protective earth of the system. To comply with IEC950, EN60950, UL1950, BS7002 and BS6204 requirements then this must be marked with the symbol defined in the IEC417 No. 5019a. The customer should therefore affix an adhesive label which will pass the 15 Second rub test (IEC950 section 1.7.15) showing the symbol below adjacent to the earth connection. This symbol must only be used at the first interruption / connection of the incoming earth wire.
Q. How do I ensure that I meet radiated and conducted emissions standards?
A. The 3gen power unit meets EN55022 Level B emissions standards. Unfortunately, this cannot guarantee that your end equipment will meet those standards automatically: no power supply manufacturer can do that! However good practice can help significantly in meeting conducted and radiated standards. The most common cause of failure in our experience is caused by poor earthing practice and ground loops. The second cause is poor cable routing - keep cables away from noise generators.... and remember orthogonal routing is better that parallel routing for reducing pick-up!
If you have any questions that are not covered in the above FAQs, we want to hear them! Please email support@excelsys.com and one of our support team will be in contact with you shortly.
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