Lab.gruppen PLM Series Operation Manual

Also see for PLM 10000Q: Supplementary guide User manual addendum Specifications Quick start Technical data

Contents

Lab.gruppen PLM Series Operation Manual Manual pdf 30 page image

24Operation and PerformancePLM Series Operation M anual R ev 1.3.55.3.11 Short Circuit ProtectionA low impedance or short circuit at the power output terminals is detected when the output current is high(Current Peak Limiter is active) and, simultaneously, the peak output voltage is below a predeterminedthreshold (42 V with the PLM 10000Q, for example). When this situation occurs, the output stage is mutedto protect it from damage. Operation of the short circuit protection system is indicated by an output channelLED (in the right-hand soft function buttons) showing steady red. The adjacent fault message will showSHORT CIRCUIT. It is also reported as a fault via the control network to the Lake Controller software. Thepresence of a short circuit (or low impedance) is re-tested every six seconds, and the output remains muteduntil the fault clears.5.4 Power SupplyThe R.SMPS (Regulated Switch Mode Power Supply) is designed to keep supply voltage rails at optimumlevels even when the mains voltage drops. Mains voltages can drop as much as 20% below nominal beforethere is any effect on rail voltages. Thus the R.SMPS can deliver full rail voltage to the output stage at alltimes, allowing the PLM to exhibit consistent transient response and a clean LF response.The PLM 20000Q is also equipped with a universal power supply with power factor correction (PFC). Thedevice can take any mains voltage, from 65 V to 265 V, allowing it to function worldwide in many differentconfigurations. The PFC reduces current peaks on the lines and reduces the requirements placed on themains distribution system. The PLM 20000Q has an unparalleled power factor extremely close to one.5.4.1 Low Inrush CurrentHigh power amplifiers with inadequate inrush current limiting can draw considerable current from the mainsat turn-on, sometimes tripping a fast-acting mains breaker. The PLM, however, has very low inrush current(the capacitors charge slowly and in a controlled manner) to prevent tripping of breakers.Several PLMs can, under normal conditions, be powered up simultaneously. If you do experience problemspowering up multiple PLMs simultaneously, they must either be turned on manually in an ordered manner,or sequenced remotely using the Lake Controller software’s Global Control feature. Alternatively, the capac-ity of the mains supply should be increased.If insufficient power is available to allow simultane-ous power-up, then there is probably insufficientcapacity for full power output during operation. It isrecommended that additional capacity is added tothe mains power distribution system.