Gazza

You should try using a voltage divider. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/voldiv.html

You guys are thinking too hard. There are two solutions: 1.) If the transformer has "taps" on the winding, you can connect the output to the 85% tap. 110v / 130v = 84% 2.) Get a different transformer.

Please keep it to one thread per topic. No need to start a new one :)

Sounds good to me, so you just need to program the PWM sequence and build the power circuit. It is going to be a lot of work, I will be interested to see how it turns out :)

What is the rating of your motor?

This topic has been moved to Electronics chit chat. [iurl]http://www.electronics-lab.com/forum/index.php?topic=9713.0[/iurl]

I think this is a better place for you to get an answer :)

How much load do you want to run off of the UPS?

How many KVA is your existing transformer?

This topic has been moved to Electronic Gadgets. [iurl]http://www.electronics-lab.com/forum/index.php?topic=9279.0[/iurl]

Hi there Sutji, I am just going to move your post into the proper fourm :) This seems to be more of a consumer electronics type question, well unless you need the E-Book to run a motor :o Aaron

Lets hear what degree you have or are taking and where you took it. I went to Niagara College in Welland, Ontario, Canada I am a Graduate Electrical Engineering Technologist My specialty was taken in Power Electronics and Power Quality How about you guys?

Calm down people. It is not Mixos's fault, if it is against the law he has to remove the content. This site is very good for asking electronic related questions, I have yet to find a better one.

Hi Adelaid, Follow this link, if you have any more question, feel free to ask :) http://webphysics.davidson.edu/physlet_resources/bu_semester2/c21_impedance_tri.html Aaron

Can you be more specific on the type of battery. Make. Model, Ah rating and Wattage rating

If I was doing this, I would use a Microcontroller. I have no experience in soil sampling, so I don't know what the proper device is, I did find this. http://www.berryhilldrip.com/Irrometr.htm#Model%20'R You could set up the controller to monitor the output level of the sensor and set up some limits, at a low level for moisture, trigger a solenoid to a water reservoir, at the high level of moisture turn off the solenoid.

I know this is an older post, but I have a lot of UPS experience. It sounds like you found an old Emerson UPS with bad batteries. Most likely there is only a few bad batteries in the string so you wont need to replace all of the batteries. What you need to do is get a constant current supply and inject each battery block with 10A of current. With a DMM measure the voltage across each cell. You should get a voltage in the 80-150 mv range. If the drop is above 1V there is an open cell and you need to replace that block. Since all of the batteries are in series they all need to be functional for the string to operate. As far as the generator is concerned, are you trying to use a DC generator to power the DC bridge? Or using a transfer switch have a standby AC generator. I guess it doesn't matter because neither will work. DC Generator: If you use a DC generator to feed the DC Link during a power failure, what is going to turn the generator? The Power is off, that's why you bought a UPS. I can think of at least 3 more major problems this would cause. AC Generator: This wont work without batteries either. The function of the batteries is to bridge the gap between the beginning of the power failure and the time it takes the generator to ramp up to full voltage. If you want your UPS to work, you are going to have to invest in the new batteries.

For the money, if you want to teach yourself, try www.automationdirect.com. It is a fantastic site. Also if you just want to try using a simulator, google "The Learning Pit" They offer an excellent AB PLC 5 simulator. I am pretty sure it only costs $25 and it comes with a bunch of examples.

In the power field we use a drive circuit. This means we rectify the signal, then using an inverter reconstruct the wave at the frequency that is desired. In a low power application I am not sure what the most efficient method would be.

That is an excellent answer. I am convinced.

Perfect, thank you.

That quote from this page says it all. http://www2.okisemi.com/site/faq/speechfaqs/speechgeneral/general6