Doing It Right Phasor Labs 5420 Glenway Circle Oregon, Wisconsin 53575 608-835-9605 voice 608-835-9039 fax cforster@phasorlabs.com March 2004 cforster@phasorlabs.com 1
Doing It Right March 2004 cforster@phasorlabs.com 2
What stray electricity do you find on a farm that is served and wired electrically correct? In November of 2003 I performed a survey of four farms for a farm owner with a total of 11,000 diary cows being milked three times a day. March 2004 cforster@phasorlabs.com 3
One of the farms is served from an investor owned substation along with other utility customers. The remaining three farms are served by a dedicated substation with three 12 kv feeders, one to each farm. March 2004 cforster@phasorlabs.com 4
Distribution lines are 12.47 kv multi-grounded with the neutral grounded at each pole. Each farm has a 750 or 1000 kva pad mounted transformer. Transformers are grounded wye primary and grounded wye secondary. March 2004 cforster@phasorlabs.com 5
All farm services are 480 volt three phase. q 120/208 volt loads are served by dry type step-down transformers. q HID Lighting is 208 volt phase to phase. q Watering unit heaters are 120 volt. March 2004 cforster@phasorlabs.com 6
All grounding on and off farm is to Code and remains connected. March 2004 cforster@phasorlabs.com 7
The first tests performed were Cow Contact Profiles. A Fluke 189 meter, a 500 ohm resistor and C. Forster s Many Point tester were used. March 2004 cforster@phasorlabs.com 8
Measurements were made at each watering unit Approximately 180 electric watering units required 4 miles of walking to measure all cow contact points. Points between watering units measured lower CC voltages. (Weather was warm, heaters were energized but not heating.) March 2004 cforster@phasorlabs.com 9
Four 72 cow rotary units were Measurements were made from parlor steel platform to floor and bump rail to floor. used for milking. March 2004 cforster@phasorlabs.com 10
Record your steady state measurements If there is a pattern to the measurements, you might investigate for on farm sources. March 2004 cforster@phasorlabs.com 11
46 50 55 95 20 18 39 25 41 52 63 45 48 76 34 54 127 28 36 35 49 70 47 58 42 44 40 25 32 22 20 5 26 Step potential measurements are from water unit metallic housing to floor. All values are in millivolts (mv) 57 41 19 270 35 12 28 true 23 rms 23 16 and 114 using 34 a 500 ohm cow resistor. Meter was a Fluke 189 digital voltmeter.4 March 2004 cforster@phasorlabs.com 12
CC voltages recorded at the watering units in free stall areas: Minimum CC voltage was 5 millivolts rms. Average CC voltage was 70 millivolts rms. Maximum CC voltage was 270 millivolts rms. (These values are with a 500 ohm cow resistor) March 2004 cforster@phasorlabs.com 13
CC voltages recorded in the milking parlor areas: Minimum CC voltage was 2 millivolts rms. Average CC voltage was 25 millivolts rms. Maximum CC voltage was 83 millivolts rms. (These values are with a 500 ohm cow resistor) March 2004 cforster@phasorlabs.com 14
Good science would tell us: The steady state voltage would have to reach 1,400 millivolts rms (for steady state conditions) to have 5% of the most sensitive cows even detect the presence of stray electricity. March 2004 cforster@phasorlabs.com 15
Some SV advisors selling solutions might say The above voltages would certainly prevent good production March 2004 cforster@phasorlabs.com 16
You may want to check for fencer, cow trainer, ID system or VFD on farm source influence in the cow contact area. March 2004 cforster@phasorlabs.com 17
Cow ID System Influence March 2004 cforster@phasorlabs.com 18
Is it significant??? 10,000 V Behavioral response for 5% of the most sensitive cows using sine waves from muzzle to hooves exposure Typ. Fencer 1,000 V 100 V 1 Cycle, Biphasic 1 Cycle, Monophasic Multiple Cycle 5 2 10 V 1 V (1,000 mv) Worst Case ID Loop USDA LOC PSCW LOC 0.1 V Higher Frequency Lower Frequency 0.01 V (10 mv) 0.001 V (1 mv) 1000 on your AM radio dial 300 Hz (5th Harmonic) 1 millisecond 60 Hz 0.1 1 10 100 1,000 10,000 Phase Duration (microseconds) = Time between voltage zero crossings Reprinted with permission C. Forster 7/5/00, 6/2003 March 2004 cforster@phasorlabs.com 19
VFD System Influence March 2004 cforster@phasorlabs.com 20
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Significant? Behavioral response for 5% of the most sensitive cows using sine waves from muzzle to hooves exposure 10,000 V Typ. Fencer 1,000 V 100 V 1 Cycle, Biphasic 1 Cycle, Monophasic Multiple Cycle 5 2 10 V 1 V (1,000 mv) VFD influence USDA LOC PSCW LOC 0.1 V Higher Frequency Lower Frequency 0.01 V (10 mv) 0.001 V (1 mv) 1000 on your AM radio dial 300 Hz (5th Harmonic) 1 millisecond 60 Hz 0.1 1 10 100 1,000 10,000 Phase Duration (microseconds) = Time between voltage zero crossings Reprinted with permission C. Forster 7/5/00, 6/2003 March 2004 cforster@phasorlabs.com 23
So, what myths have been debunked? Myth #1 - You cannot use a multigrounded distribution system to serve farms. March 2004 cforster@phasorlabs.com 24
More myths.. Myth #2 - Grounding the neutral creates too many earth currents. Myth #3 - All farms must be isolated. Myth #4 - All farms should be wired with an ungrounded electrical system. March 2004 cforster@phasorlabs.com 25
More myths.. Behavioral response for 5% of the most sensitive cows using sine waves from muzzle to hooves exposure Myth #5 - Voltage levels below the sensitivity curve for the most sensitive cows will affect milk production. 10,000 V 1,000 V 100 V 5 2 10 V 1 V (1,000 mv) 0.1 V 0.01 V (10 mv) 0.001 V (1 mv) Higher Frequency 0.1 1 10 100 1,000 10,000 Reprinted with permission C. Forster 7/5/00, 6/2003 1000 on your AM radio dial Typ. Fencer Lower Frequency Phase Duration (microseconds) = Time between voltage zero crossings Vertical scale is in volts (Zero to Peak) across a 500 ohm "Cow" resistor 300 Hz (5th Harmonic) 1 millisecond 1 Cycle, Biphasic 1 Cycle, Monophasic Multiple Cycle 60 Hz USDA LOC PSCW LOC March 2004 cforster@phasorlabs.com 26
Behavioral response for 5% of the most sensitive cows using sine waves from muzzle to hooves exposure 10,000 V Typ. Fencer 1,000 V 100 V 1 Cycle, Biphasic 1 Cycle, Monophasic Multiple Cycle 5 10 V 2 1 V (1,000 mv) USDA LOC PSCW LOC 0.1 V Higher Frequency Lower Frequency 0.01 V (10 mv) 0.001 V (1 mv) 1000 on your AM radio dial 300 Hz (5th Harmonic) 1 millisecond 60 Hz 0.1 1 10 100 1,000 10,000 Phase Duration (microseconds) = Time between voltage zero crossings Reprinted with permission C. Forster 7/5/00, 6/2003 Vertical scale is in volts (Zero to Peak) across a 500 ohm "Cow" resistor March 2004 cforster@phasorlabs.com 27
Just do it right! -End- March 2004 cforster@phasorlabs.com 28