Recent content by ssstern

So is there anyway to derate the motor if the input voltage got changed. and why does current increase as the voltage drop? I am assuming I can't use the regular V=IR relationship since motor doesn't really behave linearly. Could I make a rough assumption that if my input voltage drop 10%, my...

How about voltage unbalance issue? Can I just use the %unbalance equation (max deviation from average)/(Average voltage) and replace the voltage on the denominator to find out the change of %voltage unbalance? Can I make the assumption that max deviation from average voltage doesn't change? If I...

I just realize from the faq section: "If the load remains the same and the voltage is lowered the motor will draw more current to continue meeting the load's hp requirement. Remember the motor will still be running at the same speed since the frequency wasn't changed." Would I run into any...

Thanks for the tip. Another question I have is that how would HP of the motor be derated if the input voltage got varied from 460V to 415V for instance? If it's using the same frequency. Would that be harmful to the motor if the input voltage was varied from the motor rated voltage?

Hi, I am trying to figure out when I am varying the voltage and cycle of a three phase AC motor, what kind of derating would I need to do. I know if I am switching from 60Hz to 50Hz, the HP(final)=HP(initial)*50/60. Is there anyway to calculate change of RPM and other parameters? How do I derate...

Hi, I am trying to proof that (Vertical hollow shaft) VHS motor does not need to be energy efficient for meeting the "NEMA" standard. In the NEMA MG-1, it specified what would quaify as an energy efficient motor, but it never stated what is the "standard." I don't believe they have a standard...

I am having the same issue too and that website helps a lot. Thank you. Does anyone know where can I learn about Vertical Hallow shaft (VHS) motors?

Hi, I am working on trying to get our motors certified as Class 1 division 2. I looked into UL and CSA website and trying to figure out what type of requirement we need to meet for the motors be certified as Class 1 div 2, however I didn't find a whole lot. Is there any requirement data or...

How about replace a switch capacitor to a 1 Meg resistor in the schmitt trigger, would that work?

We were not using inductor, I was just reading some papers and most people were using indcutors for LC oscillator. Thanks for the answer, I would see if binary divider will solve our problem.

We were using schmitt trigger with C between input and ground. We would like to know if there is any other possible way avoiding use huge resistor and inductor in our circuits. I am wondering if converting Capacitance to Voltage then use a ring oscillator, or use some sort of VCO that requires...

I am looking into converting 9pF to 22pF capacitance to frequency data. So I started doing research on Oscillator. I have area constraint since I am trying to do it on CMOS technology. The frequency can't be too high. preferable under 100kHz. Inductor is too big for CMOS and due to the low...