Electrical design and installation of solar pumps

3. Check that the pump is working well at a variable speed.
For this purpose, a blanket or a tarpaulin is to be brought on 
the day of the pumping commissioning. Partially cover some solar panels (around 20%), and simulate a drop in light 
intensity: the speed of rotation of the pump should go down (but not completely stop). When removing the blanket 
from panels, the pump should return to its rated speed..
 
Tarpaulin test for partial covering to verify that the pump adapts its power depending on sun power.
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32
SOLAR PUMPING
Guidelines - Electrical design and installation of solar pumps
4. Finally, it is necessary to control the pump output flow. 
For this, use a clock (watch or phone) and a piezometric 
meter winder (or «dipmeter»). The goal is to make sure that the time needed to fill the tank is acceptable. This 
can be done:
•
By passing once in the morning and once in the evening to check that the tank has filled up during the day.
•
Or if the available time is limited, by controlling the water level in the tank after a certain time:
- Measure the water level before starting the test and check the time. 
- Start the pump and wait for the water level to increase by at least 0,5 m, 1 meter ideally.
- Stop the pump, check the time, and measure the height of water in the tank.
- By calculation (tank surface x height) you will find the quantity of added water, and finally the water flow to 
ensure that expected result is delivered.
Once these 4 tests are done, you are guaranteed to get a functional solar pumping for many years. To ensure that you complete 
all the tests, a commissioning form is presented in the annex of this document.