Hello everyone,
I measured the voltage at the starting device on the back of my refrigerator (similar to the one in the attached picture) using a multimeter and noticed some unusual readings. Terminals 1 and 2 are directly connected to the power cable and therefore have constant voltage; here, about 230V is measured, as expected. Terminals 3 and 4 have voltage when the relay switches on (meaning when the compressor is supposed to run). When the unit is running and you measure here, you get a voltage of over 270V (!). Even when measuring between 4 and 2 or between 1 and 3 (in the switched state), you get this value. How can this be explained?
Best regards,
N
I measured the voltage at the starting device on the back of my refrigerator (similar to the one in the attached picture) using a multimeter and noticed some unusual readings. Terminals 1 and 2 are directly connected to the power cable and therefore have constant voltage; here, about 230V is measured, as expected. Terminals 3 and 4 have voltage when the relay switches on (meaning when the compressor is supposed to run). When the unit is running and you measure here, you get a voltage of over 270V (!). Even when measuring between 4 and 2 or between 1 and 3 (in the switched state), you get this value. How can this be explained?
Best regards,
N
H
hampshire15 Mar 2021 12:40The goal is to prevent mold growth. Mold does not develop directly because of the compressor but rather due to humidity levels. Therefore, I believe it is practical to use humidity as the trigger for switching on.
Tapping power from a device without knowing the circuit or the device’s necessary parameters poses an unnecessary risk. Although I don’t think an additional load or high-frequency interference from power supplies should be a major problem, as the saying goes, “the devil is in the details,” and a cleaner solution is preferable. Additionally, I believe tampering with the compressor could void the warranty, which is not ideal. Your suggestion is certainly feasible, and I recognize a certain “African” pragmatism in it (which I am well familiar with from my family and sometimes appreciate as well).
A simple plug-in hygrostat, such as one from Trotec, costs about 20€ and works perfectly fine—you don’t have to mess around with a Raspberry Pi and sensors unless you enjoy that kind of tinkering anyway.
Tapping power from a device without knowing the circuit or the device’s necessary parameters poses an unnecessary risk. Although I don’t think an additional load or high-frequency interference from power supplies should be a major problem, as the saying goes, “the devil is in the details,” and a cleaner solution is preferable. Additionally, I believe tampering with the compressor could void the warranty, which is not ideal. Your suggestion is certainly feasible, and I recognize a certain “African” pragmatism in it (which I am well familiar with from my family and sometimes appreciate as well).
A simple plug-in hygrostat, such as one from Trotec, costs about 20€ and works perfectly fine—you don’t have to mess around with a Raspberry Pi and sensors unless you enjoy that kind of tinkering anyway.
N
Nanopixel15 Mar 2021 13:02Thanks for the post.
The tip about the Trotec socket hygrostat is a good one; I hadn’t really considered something like that before, nor did I expect it to be available at an affordable price.
However, using it would create another requirement: a socket in the area most at risk of moisture. Or an extension cable from the nearest one (above the refrigerator) down to the baseboard. Neither option looks very neat. I’ll have to think about it. (or maybe tapping into the socket behind the fridge as well 😀:p 😉 )
The tip about the Trotec socket hygrostat is a good one; I hadn’t really considered something like that before, nor did I expect it to be available at an affordable price.
However, using it would create another requirement: a socket in the area most at risk of moisture. Or an extension cable from the nearest one (above the refrigerator) down to the baseboard. Neither option looks very neat. I’ll have to think about it. (or maybe tapping into the socket behind the fridge as well 😀:p 😉 )
H
hampshire15 Mar 2021 13:05Extension cables up to the area near the mold or moisture buildup. This setup allows you to set a threshold value at the location of the hygrostat, which is related to the value at the mold spot – so it doesn’t have to be squeezed into the narrow gap.