Danaher Motion S200-VTS Product Manual

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Danaher Motion S200-VTS Product Manual Manual pdf 116 page image

Appendix A – DC Power Supply Design 05/2008 Danaher Motion116 S200-VTS Product ManualThe time domain of motor-related energy flow is measured in milliseconds. The inductivevoltage drop in the bus and ground wiring for these times is small. For this reason, the energyleveling bus capacitor does not need to be located near the drive and a single bus capacitorcan be shared by multiple drives.NOTEBe aware of bus resonance.Current can oscillate between capacitors in any distributed DC power system with the capacitorlocated apart and connected in parallel with wires. The capacitors and wiring inductance forman underdamped LC circuit that can ring when excited by PWM currents.The easiest way to monitor the current in the bus wiring of the drive is with a current probe.The ringing occurs if the current probe shows a large (> 10 A) quasi-sinusoidal current in the 1to 10 kHz range. While more difficult to see in voltage, it does cause small sinusoidal voltage(few volts) to occur across the drive positive Bus (J1-3) to Gnd (J1-2) terminals.Occasional bursts of bus ringing are usually not too serious, but sustained or too frequentringing is undesirable because high currents can cause heating of wires and capacitors.The simplest way to squelch bus ringing is to lower or change the inductance of the bus wiringwith the following:a. Move the external bus capacitor closer to the driveorb. Twist the bus and ground wires between the drive and supplyorc. Add extra capacitance (470 μf or more) near the drive bus terminals12. Recommended External Bus CapacitorsAluminum electrolytic, computer-grade, screw top cans are available with panel mounthardware. The voltage rating should exceed the maximum bus voltage. Choose a cap with a100 V rating for operation at 75 V bus nominal. The important capacitor parameter iscapacitance (energy storage), so an 85° C, general-purpose type (such as are listed below) isacceptable.Panasonic G-AA series1.375 x 4.125 8,200 μf 100 V EEGAA2A822CKE2 x 4.125 22,000 μf 100 V EEGAA2A223FKE3 x 4.125 47,000 μf 100 V EEGAA2A473HKECornell Dubilier DCMC series1.375 x 4.125 8,600 μf 100 V DCMC862U100AC2B2 x 4.125 20,000 μf 100 V DCMC203U100BC2B3 x 4.125 49,000 μf 100 V DCMC493U100DC2BUnited Chemicon U36D series1.375 x 4.625 8,200 μf 100 V U36D100LG822M35X117HP2 x 4.625 18,000 μf 100 V U36D100LG183M51X117HP3 x 4.625 47,000 μf 100 V U36D100LG473M76X117HPA.2 Two Power Supply OperationPowering the drive control power separately from the bus power has the advantage that faultand status information is preserved when bus power is down for safety.Wire the control supply positive terminal to J1-1 (+CTRL) and the control supply negativeterminal to J1-2 (Bus/Ctrl Gnd). Wire the main supply positive terminal to J1-3 and its negativeterminal to J1-2. J1-2 is a shared ground for control power and main power. Separate groundwires from the two supplies should join at or near the shared drive ground pin (J1-2).NOTEThe drive can be damaged if the supply voltage exceeds90 V, even briefly.