Rating of Power Saver

For IM inrush current is for less duration and we use starters for limiting the current. Set the back-up fuse for slightly more than rated line current.

But we cant provide any circuit in the saver

You can use the history data of KWH meter of last one month,

Now anyway we are improving power factor upto unity.

Are we sure we're not being duped into becoming accessories to a scam?

Hey If u know anything about this topic just involve otherwise please dont reply just non sense answers

Vaithilingam if you are the manufacturer of the energy saver, it seems odd to me that your asking for advise here.

Why are you taking the pf to unity there's no economic reason unless the supply is from a generator.

I won't be buying any power savers from vaithilingam.

My thoughts exactly!

Look at his other posts, he is either a student trying to get us to do his homework by stealth or someone in dream land

Hey If u know anything about this topic just involve otherwise please dont reply just non sense answers

making PF to unity there is a significant reduction in current-intake/inrush-current of motor.

anyway active power used remains the same hence without demand-meter installed power supply unit can't put extra money.So algebraically its a loss after all.

"Vaithilingam if you are the manufacturer of the energy saver, it seems odd to me that your asking for advise here."

My thoughts EXACTLY!

Further proof that the people who get sucked into selling this, and apparently even making them, are NOT engineers. Because if they were, they would already know there is no valid engineering justification for these scam devices.

Side note: besides possibly being a student trying to scam us, it's also possible this is a back-handed way of gaining legitimacy of the concept. In other words if people engage in a discussion as if it is valid, the scammers later use that as a way to add credence to their scam. For that reason I do not engage in anything that even looks like help.

Hey If u know anything about this topic just involve otherwise please dont reply just non sense answers

hi actually the monthly Electricity bill is almost 8 Lacs.Lot of factors were included in Electricity Bill, If we are improving power factor we can reduce Demand as well as rebate for power factor improvement.Now we are doing doing PF correction in load side not in LT panel side. The main concept is Impedance matching from that we can get maximum voltage because of Cable drops and all.If your power factor is 1.00 at LT panel but it wont be 1.00 at load side also.We have installed and we succeed also.

IIUC (if I understand correctly), power meters (watt hour meters) do not respond to kvars. In other words, changing the power factor will not change the amount of power (KW) used by the motors.

So, the saving to your customer comes in only if the utility selling electricity to your customer has a penalty based on low power factor (power factor below a certain level--maybe even more than one tier, like a penalty below 0.80, and a lesser penalty if below 0.90.)

So, you have to find out the rate structure, and the customer's current power factor. Because you only mentioned the 2 200hp motors, maybe that is the major load, but you really have to look at the entire picture.

I mean, maybe the power company's billing structure makes it advantageous to increase the power factor of the entire (plant) load to above 0.80. But, those two motors aren't (I'm sure) the entire plant load. Maybe you have to raise the pf of those motors to some higher value (like 0.85) so that the power factor of the entire plant is equal to or higher than 0.8.

And in that, you have to consider which loads run simultaneously.

I'm trying to remember how we were billed at our coal mines. I know we paid for kwhrs, and then we were penalized by the peak kwhr usage period (it was either the highest 15 minutes or highest 1 hour use of kws during the month, and then there was another penalty factor for power factor below 0.8, iirc.

rhkramer, I am pretty sure you are right - watthour meters respond to the kW, not the kVA. When I was field calibrating WH meters, we tested at full (100% rated) load, light (10%), and lag (30 deg phase angle between V and I) load. The calibration compared the pulses output by the meter or the rotations of its disk to a highly accurate calibration standard, both fed the same voltage and current sources. On light load, the disk spun 1/10 as fast as at full, and in lag load, somewhat slower than full load. If it were spinning based on VA rather than W, you would expect the disk to spin the same rate no matter the phase angle. I never really thought about it before, because we didn't actuall look at the watts, only the comparison of the meter's pulses to the standard's.

Oops! I meant 60 degree lagging phase angle. That gives PF of 0.5, and should slow the disk to half speed. Wish we could edit replies longer than 15 minutes after posting.

hi actually the monthly Electricity bill is almost 8 Lacs.Lot of factors were included in Electricity Bill, If we are improving power factor we can reduce Demand as well as rebate for power factor improvement.Now we are doing doing PF correction in load side not in LT panel side. The main concept is Impedance matching from that we can get maximum voltage because of Cable drops and all.If your power factor is 1.00 at LT panel but it wont be 1.00 at load side also.We have installed and we succeed also

Recommendation: Zero.

V Quote "We are manufacturing of energy saver. Yesterday I consult with one customer they are having 2 nos of 200 hp motors. The maximum running load is 260 kw(both motors) and the power factor is 0.75."

V how did you get these numbers? If you are a real consultant you should be able to explain your findings. If you corrected the PF to 1.0 you should know know the KVA to give the customer. What is the name of your company? Did you check to see if the utillity is billing KVA? Please respond to these questions.

Hi see I can recommend 300 KVA to them but the main factor is inrush current . if i can give 300 KVA while motor get starting definitely it will exceed 300 KVA thats what i am little bit confused

Maybe i am thick, but i always thought that all you need was some appropriate capacitors to improve pf. Are you talking about something else here?

0.75 pf for such motors seems low, are you sure? i would expect better than 0.8 pf. Also, it doesn't make sense to target 1 pf, 0.95 is about the best one should target.

kvsridhar,

Your problem here is that you are thinking like an engineer. Such foolish behavior must be abandoned in order to believe in these devices.

Hey If u know anything about this topic just involve otherwise please dont reply just non sense answers

As reported to the site administrators:

This and the next 3 duplicate posts are an unwarranted attack on a knowledgeable member. Please delete all four, if not every posting by this fraudulent ignoramus. If there are no competent engineers among the moderators, then let the legal department consider the ramifications of maintaining bogus noise on the site.

If we are improve the power factor the current will come down and also we can reduce demand also.we can get rebate from Electricity Board also.

Quite right that you will gain if you improve power factor. My points are :

1. 0.75 pf is too low for a motor at full load. Please re-check, and question the supplier if it is really 0.75.

2. Improving to 0.95 will cost say X, improving further to 1 will cost much more, (maybe 2X or more) and is not worth it usually. Please work out the costs involved rather than just worrying about theoretical values.

3. By improving pf you may be able to save on cables and busbars also.

4. The approx 6X inrush currents of the motors, even if they last 10 seconds, are unlikely to overload the cables. You need to calculate voltage drops and ensure that the motors will not stall.

You are making energy savers. What are they?

HBL Energy Savers

i meant, what does it do, how does it work, what does it consist of...etc? How does it save power and energy ?

We are doing power factor improvement in load side and we are reducing the voltage also means 220 V for single phase and 380 V for 3 phase.In this voltage even motor also will be operate at same speed.this is the logic we are using

That doesn't make any sense at all.

Reduction of voltage will impact on the output of moters, and beside that efficiency of any transformation device will come in picture, So what is the net gain?

Pardon me, i am even more confused now.

1. Reduced voltage to a motor will result in increase in current to compensate...please see this link : http://www.motorsanddrives.com/cowern/motorterms12.html

2. How do you improve pf on load side ? Capacitor on motor terminals ?

3. You mention 220V single-phse loads also....how many are there ? Are you taking that wattage also into calculation ? Are the sigle-phase loads balanced on each phase ?

Please note that i am really trying to understand so that i can help. i am not trying to cross-question you for spite.

We have a panel according to the loads like 50,60KVA Etc.It has APFC(Automatic Power factor Control) Panel and Coil based Transformer or servo stabilizer.If voltage variation is high in customer site we provide servo stabilizer. Actually what we will do means once we go to site and get all the details like connected load and maximum running load through power analyser KW,KVA,PF,KVAR,THD,CF.If we can possible to show then we can propose to the customer.We are offering motor loads 15 % lighting loads 30%mixed loads (Lighting load+ACs) 20%.We have been succeed also.

Wow. That is impressive. Assuming you mean savings of 15%, 30% and so on. i would have assumed PT Barnum's rule works here somehow, if you had not told me that you are successful. Good luck.

<sniff>

I was getting my feelings hurt...