Section VII
TABLE 7-3. MISAL ∆180 AND ∆270 CIRCUIT TESTS (cont)
Normal
Circuit or
If Indication
Procedure
Step
Indication
Function Tested
Is Abnormal
∆270 Circuit Test
2
Part
Same as step 1, part I
Same as step 1,
I
Same as step 1, part I.
Same as step 1, part I
except:
except:
part I except:
HEADING SELECTOR to
A 30-MINUTE ERROR
Readout shall show
90 DEGREES.
a final reading of
is switched into
30 3 minutes
circuit at full switch
∆270MINUTES switch to
rotation.
more negative than
0.
initial recorded
reading of this
∆270 polarity switch to
step.
+∆270.
Record initial ERROR.
Rotate ∆270MINUTES
switch clockwise from
0 to 60 MINUTES.
∆270 polarity switch to
2
ERROR readout
Same as step 1,
Same as step 1, part II.
-∆270.
shall drive to a
part II.
Part
final readout of
II
30 3 MINUTES
more positive than
initial recorded
reading.
∆270MINUTES switch to 0.
∆180 Circuit Test
3
Part
Same as step 2, part I.
I
Same as step 2, part I
Same as step 2,
Same as step 2, part I.
except:
part I except:
Applicable to ∆180
Readout shall show
switches.
a final reading of
60 4 MINUTES
HEADING SELECTOR to
more negative than
180 degrees.
initial recorded
reading of this
step.
∆180 polarity switch to
Same as step 2,
ERROR readout
Same as step 2, part II.
3
-∆180.
shall drive to a
part II.
Part
final reading of
II
60 4 MINUTES
more positive than
initial recorded
reading.
∆180MINUTES switch
to 0.
7-13
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