Electrical switch and LCB get installed

Simplifications of systems sometime cause a lot of inconvenience and insecurity. This was the case also to our system which in the beginning had as simple electrical connections as possible:

any time there was a need to change the power source, a procedure of at least 10 min had to be followed with a lot of screwing and unscrewing in fuses, raw cable manipulation, and tapes..

Luckily this was solved this week, with some great family help, a switch got installed between the PVs and the rectifier. We also installed the LCB between the PVs and the switch as well as some extra fuses before the motor as suggested by the LCB manufacturer:

Electrical connections diagram

Some photos of this amateur installation:

Putting a wood plate as a base in order to avoid drilling too many holes on the wall

The switch

Installing the switch

The switch between the LCB and the fusebox

 

One interesting visit from the stuff of the Laboratory of Electric Circuits and Renewable Energy Sources from the Electronic Engineering Department

Last week the Laboratory of Electric Circuits and Renewable Energy Sources from the Electronic Engineering department visited our installation, together with the professor dr.Kalaitzakis and 5 master students (http://www.ece.tuc.gr/Controller?actionClass=loadFirstPage&action=loadFirstPage).

They were very interested in our project, since they are also involved in desalination (of course from the power and control systems point of view) and we discussed many topics like the introduction of the automatic controller so that I free my hands and also get more accurate results. Furthermore, they expressed their worries about the motor lifespan under such fluctuating operations. They are afraid that it won't last for long without damages and that we should take care for its protection. They suggested to install a supercapacitor (small), which will only serve purposes of smoothing these deep current fluctuations in order to provide stable current to the motor. 

The LCB may help the situation with the fluctuations but for sure it will not replace the manual regulation of the motor speed by me during day operation. 

We also discussed about the Voltage and current losses which i observe in datalogger and they think that they are remarkable. However, it is not very obvious what is the reason, it may be the sensors construction or some resistance occuring via the connections. 

Another suggestion was to introduce a W-meter at the PV panels, so that i know also the power from the PV panels and estimate better how much losses i get while measuring with the datalogger and account for them.

Kostas and Ariadni, master students at the Laboratory, visited again the installation trying to understand better how the motor works and find out the safe operating range. After contact with Spectra (the provider of our system), we were informed that there is no operating range as such and no minimum voltage requirement. Ariadni and Kostas found this strange, since all motors have an operating range  in which they operate constant and safe. 

Maybe this has to do with this specific motor which is permanent magnet dc current? 

this is something still to answer..