frequency | Page 2

frequency

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  1. D

    VFD controlled Pump relationship clarification

    We Know that when configured for scaler control, a VFD willadapt its switching modulation to ensure that when frequency is changed, motorterminal voltage will change hence the term Voltage frequency ratio. Similarly, if we look at the affinity laws for a centrifugalpump we see that a 10 %...
  2. B

    Standard high frequency 600x600 vs panel LED's

    I have to say I was impressed with the improvement on these LED fittings from just a few years back. I will be honest though, its the 1st time I have seriously considered them as a viable alternative to tubed fittings. The ones I looked at are fully compliant with LG3 and 7 requirements for...
  3. E

    Does 10 volts and 10 heartz make much of a difference

    Speaking hypothetically if I was able to buy battery operated tools from the Us of A and not pay import duty or postage would the charger still work?
  4. D

    6 foot fluorescent lights with tube - high frequency NEW

    6 foot single fluorescent light batten fitting with tube fitted with high frequency control gear NEW light, NEW tube £13 each We are in Northern Ireland so postage would be £10.95 48hr tracked upto 70 kilos 1 fitting with tube weighs 2.5kg
  5. T

    Can you work out the value of the resistor?

    Hi guys, Just wondering if you can help me on this one, I have a RLC series circuit the values are as below; R = unknown L = 800mH C = 300uF from there I have calculated; the resonant frequency to be 10.3Hz the capacitive reactance 51.50 ohms The reason I need to know is I need to work...
  6. O

    High Frequency wiring in trunking with normal circuits??

    Hello, i am having to install 2x 16A commando outlets in a factory that are ran from a generator outputting 127v 3 phase @ 200Hz. Does anyone know if I can run the 200Hz wiring back into the main trunking to get to the next room (where the outlets are required) which already has normal...
  7. Simonslimline

    Frequency - Volts - Amps. A little help please.

    Ok i just spotted this in the main section of the forum and it got me thinking about the answers. I dont remember doing this at college. A reactor allows a current of 15a to flow from a 230v 50 Hz supply. Determine the current which will flow at the same voltage if the frequency changes...
  8. N

    LEDs & Interference

    I'm led to believe that LEDs (as in the actual basic semiconductor device themselves) are comparatively strong emitters of radio frequency interference. Don't know about how much power or where in the spectrum but that's what I was once taught. Just wondering whether anyone has seen this as a...
  9. S

    Is this a high frequency batten or HPF?

    I have just bought what I thought was a 'high frequency' fluorescent light for the kitchen, thats what it was advertised as. It arrived in packaging with 'HPF' on it which is 'High Power factor' which I dont think is high frequency. I wouldn't be too bothered but it doesn't work! The picture...
  10. rustynails

    High Frequency Sensor Module

    I've been down the local wholesalers tonight and wanted to buy a small light with a sensor/pir built in. Nothing spectacular, so he starts talking about a High Frequency Sensor Module to put in a Knightsbridge opal bulkhead, it uses microwaves. It was late In the day so I agreed to take it. Now...
  11. K

    Testing frequency

    Hello all, Just thought I'd check some opinions on testing frequency, with the changes in the guidance advice.The latest(4th) edition has revised some of the intervals for certain types of appliances such as IT. Would you consider that the changes can be applied retrospectively, ie if an...
  12. F

    High frequency lighting

    In high frequency lighting I am aware of the advantages of them so if they are high frequency does that mean there greater than 50 hz anyone
  13. K

    Current change in a reactor by altering the frequency

    Hi can anyone answer the following question. I am aware X=2piFL how do I use this to find the answer to the following: A reactor allows a current of 15 A to flow from a 230 V 50 Hz supply. Determine the current which will flow at the same voltage if the frequency changes to (a) 45 Hz, (b) 55...
  14. J

    Variable Frequency Drives

    We intend to install VFDs for the motors installed at our facility. Can anyone tell/share the IEC/NEC/IEEE code/standard showing upto what kilowatt rating of the motor we can use the DOL starter type and after what kilowatt rating we have to install VFD. For example, I seen a Electrical...
  15. D

    repairing high frequency fluorescents

    Had a call from an office to check some faulty lights, and having not done a lot of work on high frequency panel lights, I just wanted to see what people's thoughts are. The tube is flickering, replaced the tube, same problem, so must be the ballast. Just wondered whether people just replace the...
  16. G

    frequency of ecr

    Hi can anyone tell me where I can download a pdf for the frequency of ecr. Need to send something to a client but dont have a scanner to scan page from regs. Thanks
  17. G

    frequency of ecr

    Hi. Does anybody know where I can find on pdf doc bs 7671 frequency of ecrs on different property types? I need to send info over to a client via email but havent got a scanner to send the page from regs and cant find any info on internet that would be suitable for me to send as it either doesnt...
  18. L

    Lenze smd variable frequency drives 0.37Kw. 3/PE 400-480v BEST PRICE

    Up for seel VFD were used between 0 and 7 months. Many of them were used only were installed and then removed. All VFD will be delivered in original boxes. Each VFD is tested before shipment. VFD CONDITION IS LIKE NEW. 100% QUALITY GUARANTEE OR MONEY BACK ! DO NOT MISS THE BEST PRICE IN THE...
  19. M

    ABB Frequency Inverter( Winder/Unwind. Application Program )

    I am a Beginner. I install a program ABB ACS800 ( Winder/Unwind , Application Program) .This inverter is used communication card to be run. I want to upload program to this inverter. This inverter program upload to another ABB inverter to download this program. I want to change (99.02...
  20. D

    what frequency do 'HFAC' low voltage transformers (like varilight) typically output?

    Hi, I'm replacing low voltage halogen with MR11 and MR16 LED bulbs. AC supply would be simplest because of existing wiring, but I'm concerned about LED flicker: Characterizing and Minimizing LED Flicker - Lighting Solutions | DigiKey I'm looking at varilight transformers: VARILIGHT...

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