4 stroke quiet generators

[bobl]

Great feedback on batteries of late.
What are your thoughts on 4 stroke generators to run my tormek and other sharpening machines?
Here I go again, ( Churning up a storm )
I look forward to the replies.
F.Y.I. it is to run in U.K. 230 to 240 volts.

[Janne]

Hello.
I would go for a Honda.
They have some small and nice generators.
The smallest model will do the job with a nice genuine sine curve, often made for computers and battery chargers.
Best regards, Janne

[bobl]

hi Grinder, which honda model would that be. The 1000 or the 2000 ?

[Ken S]

Bob,

I found this link:

http://blog.ralphhelminc.com/honda-eu100i-vs-eu2000i-battle-of-the-compact-models/

If you plan on using just your T7 (200 watts), the 1000 watt capacity of the 1000 model should be more than adequate, more portable 30 pounds vs 53, and slightly fewer pounds sterling to purchase.

Be sure to calculate your total power needs.

Ken

[Elden]

   From a link I previously posted is this post:

"leftyretro said:
13th October 2007 05:55
run motor inverter
Not sure I totaly understand your question, but if one is planning to run a AC induction motor from a inverter (a UPS?) one has to size the inverter to be able to handle the normal in-rush start-up current that AC motors draw. This can be up to 5-7X the normal running current for some number of seconds.

Lefty"

   I assume (assumptions can get you into trouble at times! ) that this would apply to generators as well.

5 x 200 watts = 1000 watts
7 x 200 watts = 1400 watts

   If others at running the Tormek on a 1000 watt unit, then I would think it would be a fairly safe assumption that it would work.

   The information in the link Ken posted is talking about 120 volts. Checking further on a Honda web site, I did not see 240 volts output mentioned.

   It appears that the EU10i or EU20i are the units for 240 volt operation.
EU10i: MAXIMUM AC OUTPUT  1000VA   RATED AC OUTPUT   900VA
EU20i: MAXIMUM AC OUTPUT  2000VA   RATED AC OUTPUT   1600VA

[Ken S]

Bob,

You need some UK oriented expertise. Generators should list surge capacity (the power needed to start a motor) as well as the normal operating capacity. Tormek support (support@tormek.se) should know the starting surge power requirements of the Tormek motors.

I suggest you visit a generator specialty dealer whose lineup includes these small "camping" ganerators.

Ken

[Elden]

   Ken, I agree thoroughly with your comment about the UK oriented expertise being needed. I definitely do not have expertise with the USA end of it. I am not trying to be a "old stick in the mud".   When one is spending that much, you want to make sure it is done correctly.
   I find it interesting that these generators do not have dual AC voltage (120 / 240V).
   The following link is interesting.
http://powerequipment.honda.com/generators/generator-wattage-estimation-guide

[Jan]

I have measured all relevant electrical data of my T7 with a sensitive energy cost meter:

Voltage = 233.3 V
Current = 0.7 A
Power factor = 0.47
Frequency = 50 Hz
Real power = 76.87 W
Maximum (start-up) current = 7.55 A
Maximum (start-up) real power = 1123W
Sorry, I have failed to reproduce the max data, and so I consider them unreliable.   


In my understanding small generator may be not able to deliver such a high start-up current and wattage as the grid because the generated voltage will temporarily drop. For this reason I think a 1000 W generator should be sufficient for T7.

Jan

P.S.: You may be wondering why the measured data do not contain the declared 200 W input power of the T7 motor. The explanation is following: the 200 W input power refers to an apparent power under full load, for 240 V, and should correctly be written as 200 VA. In our case my idle running T7 motor has an apparent power 233.3 V * 0.7 A = 163.3 VA.

The real power = apparent power * power factor = 163.3 VA * 0.47 = 76. 8 W.

Real power of an idle running motor is converted to heat power. Under load the real power increases mainly because the power factor increases also. The real power of a loaded motor is partitioned between the shaft power and the heat power.

[Ken S]

Excellent detective work, Jan!

Ken

[bobl]

Fantastic info everyone.
Thanks again for your help.
Cheers.

[Ken S]

Bob,

Keep us posted. We will probably have the same questions from other members; it is good to have real world experience.

Ken

[bobl]

Will do Ken.

[Ken S]

Jan,

I applaud your integrity for obviously posting your corrected figures.

Ken

[bobl]

ok Jan
Also, correct to you Ken, I agree.
All good help.
Bob
The Knife Grinder.