Yesterday afternoon we performed the test described in this git issue.
We tested the functionality of one DPDT (Douple Pole Double Throw) device connected in series with the smart PDU plug of the SAT WE motor crate driving MH.MA.1 and MH:MA.2.
This device physically disconnects both the neutral and phase wires of the motor power smart plug, thus allowing to keep the crate front panel switch in the ON position while avoiding the 48Hz noise described here: https://logbook.virgo-gw.eu/virgo/?r=64447
The test concluded succesfully. The DPDT device was left connected to PDU socket #8. The motor crate front panel switch was left ON.
Here is the sequence of actions that were performed:
- 14:14:25 UTC - Initial condition: crate front panel switch in OFF position, crate plugged to socket #8 of the smart PDU
- 14:17:03 UTC (24 Sep 2024 16:17:03 CEST): front panel switch in on position. We verify that the usual noise around 48 Hz appears in Hrec. (red curve in Figure 3)
- 14:19 UTC - we unplug the Motor crate to check if the same noise is present when reversing the neutral and phase wires. yet we discover that action is not possible since the plug is a triple plug that cannot be reversed (in case an adaptor to schuko type is needed)
- 14:19 UTC ITF unlocks: checking WE F0 sensors we verified that the unlock was NOT due to us walking on the tower basement. Likely the unlock is due to us unplugging the crate while it was on (!)
- waiting for the ITF to relock we do the following: put front panel switch in OFF position and install the DPDT relais in socket #8 of the smart PDU
- 15:19 UTC relocked LOW NOISE 3
- 15:29:48 UTC - turn front panel switch in ON position: no noise appears in Hrec (!) (Blue curve in Figure 3).
- 15:36:xx UTC - switch on PDU socket #8 from MOTOR client. The Motor switches on (light on in the front panel) and a large noise appear in Hrec extending from 40 to 60 Hz with an intense 50 Hz line in the middle (note: this is an operation that is usually not done when ITF is locked)
- 15:38:30 UTC switch off PDU socket #8 from MOTOR client. The noise disappears from Hrec. Yet a large 50Hz noise remains. This noise is present as well in Hrec_raw and DARM. Paolo confirms that this residual noise is due to a malfuntioning of the 50Hz FF filter.
- 15:57 UTC Paolo resets the 50Hz FF filter and the 50Hz noise comes back to normal.
- 16:02:35 UTC we swap the schuko plug on the DPDT to reverse neutral and phase wires. Yet, this test is not conclusive since the PDU socket was off.
