Wiring Clarification

[Lotusjohn]

From VSD-E manual

GND is the electrical 0V potential shared with power supplies and all connector pins labeled as “GND”. Connect GND to power supply 0V terminal.

FG is the ground for EMI shielding which is located in D-sub connector metal shells and D-sub connector
pins labeled as “FG”. FG and GND are electrically floating against each other but are connected by EMI
suppression capacitor inside drive.

However, the drawing on Page 16 says "negative HV connected to frame ground"

These two instructions seem to contradict one another. The drawing on page 16 connects the -HV to frame ground and the other statement connects -HV to GRD

Please clarify


John

[Xerxes]

It is recommended to connect power supply negative voltage terminal to both: GND and FG.

[nick mulder]

Yeh, I wondered how the "EMI suppression capacitor inside drive" could really do anything if there is no chance for any potential difference across its terminals.

Emailed Tero (hello!) about it and got the same response you did - but still wonder about it...

Something is lacking in my electrical/electronics knowledge - I never learned much about noise/EMI - so go figure !

(?)

[Xerxes]

Originally Posted by nick mulder Yeh, I wondered how the "EMI suppression capacitor inside drive" could really do anything if there is no chance for any potential difference across its terminals.

Here is attached schematics of circuity between GND and FG inside drive. The purpose of capacitor is to prevent DC currents flowing on FG (i.e. ground loops). For high frequency interference this circuit is equivalent to straight wire and DC current sees only the 220k resistor.