BS BULLETIN i37o, U. S. DEPARTMENT OP AGRICULTURE 
Table 12. — Influence of low voltage on the moisture-test results 
110-volt circuit: 
Voltage 
90 
24.4 
2,196 
180 
12.2 
2,196 
33V6 
16.9 
30V3 
16.6 
31H 
16.8 
3 
0.3 
12 
-0.6 
95 
25.6 
2,432 
190 
12.8 
2,432 
31 
17.0 
28H 
16.8 
29H 
16.9 
0.3 
10 
-0.5 
100 
26.8 
2,680 
200 
13.4 
2,680 
27J^ 
17.1 
23% 
16.9 
26% 
17.0 
2U 
0.3 
6% 
-0.4 
105 
28.4 
2,982 
210 
14.2 
2,982 
25 
17.2 
22% 
16.9 
24 
17.1 
2% 
0.3 
4H 
-0.3 
110 
29.6 
3,256 
220 
14.8 
3,256 
23 
17.3 
20% 
17.1 
22 
17.2 
2% 
0.2 
2V 2 
-0.2 
112 
30.4 
3,420 
225 
15.2 
3,420 
2iy 2 
17.3 
im 
17.2 
20% 
17.3 
2 
0.1 
% 
-0.1 
115 
31.0 
3,565 
230 
15.5 
3,565 
20^ 
17.5 
17.3 
19 
17.4 
3 
0.2 
Trace. 
CO 
Amperage.. 
Wattage 
220- volt circuit: 
Voltage.. 
Gas tester. 
Wattage.. 
Maximum: 
Time (minutes) 
Moisture (per cent) ... 
Minimum: 
Time (minutes) 
Moisture (per cent)... 
Average: 
Time (minutes) 
Moisture (per cent)... 
Range: 
Time (minutes) 
Moisture (per cent) 
Average variation, stand- 
ard gas tester: 
Time (minutes) 
19% 
17.5 
19 
17.3 
17.4 
% 
0.2 
Moisture (per cent)... 
1 Results obtained with standard gas tester. 
The results obtained in these experiments with a Brown-Duvel 
moisture tester, electrically heated, operated at varying voltages, 
show that as the voltage and wattage increase to optimum condi- 
tions the time of heating decreases, and that the percentage of mois- 
ture obtained increases. It shows, also that the heating time is de- 
pendent upon the wattage developed and delivered by the heater. A 
drop in voltage of over 5 per cent will cause a decrease in wattage 
sufficient to cause appreciable variations in moisture-test results and 
these results will always be low. 
The experiments also demonstrated that the results obtained with 
the electrically-heated tester can be made to check with the results 
obtained with a gas-heated tester by means of wiring the electric 
heaters to such a capacity that each heater will develop approxi- 
mately 600 watts of energy per heater, or 3,600 watts per 6-compart- 
ment machine. To attain these results on a constant pressure, 110- 
volt circuit, the heaters must be wired to carry 5.4 amperes of cur- 
rent. If the voltage is not constant at 110 but fluctuates, as for in- 
stance from 103 to 95 volts, it will be necessary to rewire the heaters 
so as to produce a current which will develop 600 watts per heater. 
For illustration, the amperage necessary on a 95-volt circuit is 6.2 am- 
peres and on a 103- volt circuit it is 5.8 amperes. If the voltage is 
fluctuating badly, the average voltage will have to be 'ascertained 
for the circuit on which the moisture machine is to be operated and 
the heaters overwired; that is, so wired as to give more wattage than 
is necessary, and the excess cut out by means of a point rheostat. 
This, of course, necessitates the constant use of a voltmeter, ammeter, 
and rheostat on the line. 
HOW TO TELL IF THE ELECTRIC HEATER IS WORKING AT STANDARD CONDITION 
By the combined use of a voltmeter and an ammeter it can readily 
be determined whether the proper wattage is being developed for 
the type of heaters used. As these instruments are not always avail- 
able, however, the oil test (p. 22) is the best test to apply. The 
