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  1. RM12

    Backlash Calculation

    I have a gear train with 2 spur gears, 2 bevel gears. I wanted to know if someone could guide on how to calculate the backlash for these gears and what I need know and do to acheive this. The train has a one shaft with the bevel gear and spur gear inch apart on the shaft. The spur gear drives...
  2. RM12

    Cycling Vibration on 1800 RPM Vertical Motor

    This time it wasn't cycling 2 times when on rubber or pump head. It was 1 time and 2 times cycling without the pump head and it did not matter where I measured it radially around the motor. The initial and final test were both done at the shop. Initially we had the motor run in the shop...
  3. RM12

    Cycling Vibration on 1800 RPM Vertical Motor

    I have to admit to it also that I am yet to understand completely why it would make the vibration vary between a range. For now, my theory is that the motor since it's not a synchronous motor, the motor rpm oscillates as well which oscillates the vibration with its natural frequency. It's a...
  4. RM12

    Backlash Gear system

    Got it. What if I measure it on the fan instead of directly going to the gear itself?
  5. RM12

    Backlash Gear system

    I am trying to understand where a backlash is measured in a gear system. I have a shaft with sun gear on it and it meshes with another shaft having a pinion gear. Sun gear shat has a coupling to on end which is being driven by a motor. (But this system is uncoupled) Pinion gear shaft has a...
  6. RM12

    Cycling Vibration on 1800 RPM Vertical Motor

    Sorry for not responding earlier to the thread. This thread turned out more informative than I expected. Coming to the conclusion to the original question (OP), I had to do a bump test and low-behold the natural frequency was close to the running speed between 1659 - 1750 and it created a...
  7. RM12

    Size of Air Conditioner

    After many back and forth clarification queries, here is the true problem. The rotor of the motor is equipped with a fan and moves air axially through the stator. The inlet air temp is 78f and outlet air is 135 F. The material of the core being cooled down to 200 F from 350 f is carbon steel.
  8. RM12

    Cycling Vibration on 1800 RPM Vertical Motor

    By Cycling I mean that the values increase to 0.22 gradually, 0.07,0.075,0.089,0.01.....0.22 and then the reverse happens. It isn't a beat frequency with the way it eventually increases or decreases. Also, these values are being measured radially.
  9. RM12

    Cycling Vibration on 1800 RPM Vertical Motor

    I am running a vertical motor 4160 V and 1800 RPM unloaded. I checked the mechanical integrity of all parts, bearings housings, stator and rotor. When I measure the vibrations, I get cycling vibration at 2 x the rotation between 0.07 to 0.22 inc/s. Can anyone help understand why this maybe?
  10. RM12

    ABB VFD

    Breaker is good, connected to another machine and did not trip. Yes, suddenly developed and was not replaced. I changed the EMC board and tried. Next thing after the EMC would be the frequency converter anyways, so I don't think its cost effective to fix that.
  11. RM12

    ABB VFD

    I have an ABB ACS800-01 VFD that is operating a 25 hp 460 V AC motor. Recently I have been having breaker trips as soon as I switch the power supply on. I checked the circuit for any blown marks etc. and it seems fine. Ask for information if you have questions. Does anyone know why that is?
  12. RM12

    Balancing a Vertical Pump Motor on a rubber base

    THANK YOU! That makes complete sense now. I wanted to follow up on this: 1- The only reason a rubber pad or a flexible base is used is, if the resonant frequency is too close to the running frequency. My question is why then the phase angle changes for vibrations in comparison to with &...
  13. RM12

    Balancing a Vertical Pump Motor on a rubber base

    I completely agree with balancing it below resonance. My question is when we add a spring or a rubber base to detune it from the resonance frequency of the electric motor and balance it. How does that ensure that the electric motor when installed in the field won't change to a different...
  14. RM12

    Balancing a Vertical Pump Motor on a rubber base

    Vibromera Could you please explain why do you balance it on a flexible base? I want to see if my approach are for the same reasons.
  15. RM12

    Balancing a Vertical Pump Motor on a rubber base

    Tmoose I couldn't really understand the second statement " 1X vibration amplification...." Vibromera: I am a novice in vibrations. I am not following on how 700 rpm is equal to 6000 revolutions per min? Also do you mean maximum rotational frequency as - (60 HZ, for 2 pole 3600 rpm)?
  16. RM12

    Size of Air Conditioner

    I understand this. It's an odd situation I haven't been on the site so pulling information like if it has fins on the casing or not is not easy. I don't have the nameplate information either. The one they sent is blurred. I am told for some reason the motor started operating at 350 F and it...
  17. RM12

    Balancing a Vertical Pump Motor on a rubber base

    I understand that and its very useful information. I am still trying to figure out how would one know what the natural frequency of the entire system is? Let us say I have a Vertical Motor that is going to be coupled to a pump. I dont have the pump. I fix the motor and I need to balance it to...
  18. RM12

    Size of Air Conditioner

    Let me know what is wrong with these steps: Calculate the heat rate using the inlet and outlet air temperature. I will assume any existing CFM AC. Example 4000 CFM Heat loss rate = Mass flow rate x specific heat capacity of air x Delta T For this particular heat loss rate calculated we can...
  19. RM12

    Size of Air Conditioner

    The details are drip fed at customers information leaking speed. Anyway, I found out the core is 30 inches in length. So basically, the cylindrical area of focus is 2*pi*r*l. The core is carbon steel. Any other cooling system is not an option because of space constraints. I do not have the...
  20. RM12

    Size of Air Conditioner

    (MintJulep) Do those fans have data sheets? Nope, could not pull the data sheet because the nameplate was missing and no indication of what kind of fan it is.
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