<s>
A	O
rotary	B-Algorithm
variable	I-Algorithm
differential	I-Algorithm
transformer	I-Algorithm
(	O
RVDT	B-Algorithm
)	O
is	O
a	O
type	O
of	O
electrical	O
transformer	B-Algorithm
used	O
for	O
measuring	O
angular	O
displacement	O
.	O
</s>
<s>
The	O
transformer	B-Algorithm
has	O
a	O
rotor	O
which	O
can	O
be	O
turned	O
by	O
an	O
external	O
force	O
.	O
</s>
<s>
The	O
transformer	B-Algorithm
acts	O
as	O
an	O
electromechanical	O
transducer	O
that	O
outputs	O
an	O
alternating	O
current	O
(	O
AC	O
)	O
voltage	O
proportional	O
to	O
the	O
angular	O
displacement	O
of	O
its	O
rotor	O
shaft	O
.	O
</s>
<s>
In	O
operation	O
,	O
an	O
alternating	O
current	O
(	O
AC	O
)	O
voltage	O
is	O
applied	O
to	O
the	O
transformer	B-Algorithm
primary	O
to	O
energize	O
the	O
RVDT	B-Algorithm
.	O
</s>
<s>
When	O
energized	O
with	O
a	O
constant	O
AC	O
voltage	O
,	O
the	O
transfer	O
function	O
(	O
output	O
voltage	O
vs.	O
shaft	O
angular	O
displacement	O
)	O
of	O
any	O
particular	O
RVDT	B-Algorithm
is	O
linear	O
(	O
to	O
within	O
a	O
specified	O
tolerance	O
)	O
over	O
a	O
specified	O
range	O
of	O
angular	O
displacement	O
.	O
</s>
<s>
RVDTs	B-Algorithm
employ	O
contactless	O
,	O
electromagnetic	O
coupling	O
,	O
which	O
provides	O
long	O
life	O
and	O
reliable	O
,	O
repeatable	O
position	O
sensing	O
with	O
high	O
resolution	O
,	O
even	O
under	O
extreme	O
operating	O
conditions	O
.	O
</s>
<s>
Most	O
RVDTs	B-Algorithm
consist	O
of	O
a	O
wound	O
,	O
laminated	O
stator	O
and	O
a	O
salient	O
two-pole	O
rotor	O
.	O
</s>
<s>
RVDTs	B-Algorithm
offer	O
advantages	O
such	O
as	O
sturdiness	O
,	O
relatively	O
low	O
cost	O
,	O
small	O
size	O
,	O
and	O
low	O
sensitivity	O
to	O
temperature	O
,	O
primary	O
voltage	O
and	O
frequency	O
variations	O
.	O
</s>
<s>
Consequently	O
,	O
the	O
angular	O
information	O
output	O
by	O
a	O
RVDT	B-Algorithm
is	O
independent	O
of	O
the	O
input	O
voltage	O
,	O
frequency	O
and	O
temperature	O
.	O
</s>
<s>
Putting	O
the	O
above	O
mathematical	O
equations	O
in	O
some	O
theoretical	O
form	O
,	O
the	O
working	O
of	O
RVDT	B-Algorithm
can	O
be	O
explained	O
as	O
below	O
.	O
</s>
<s>
Basic	O
RVDT	B-Algorithm
construction	O
and	O
operation	O
is	O
provided	O
by	O
rotating	O
an	O
iron-core	O
bearing	O
supported	O
within	O
a	O
housed	O
stator	O
assembly	O
.	O
</s>
<s>
Because	O
RVDTs	B-Algorithm
perform	O
essentially	O
like	O
a	O
transformer	B-Algorithm
,	O
excitation	O
voltages	O
changes	O
will	O
cause	O
directly	O
proportional	O
changes	O
to	O
the	O
output	O
(	O
transformation	O
ratio	O
)	O
.	O
</s>
<s>
Since	O
most	O
RVDT	B-Algorithm
signal	O
conditioning	O
systems	O
measure	O
signal	O
as	O
a	O
function	O
of	O
the	O
transformation	O
ratio	O
(	O
TR	O
)	O
,	O
excitation	O
voltage	O
drift	O
beyond	O
7.5	O
%	O
typically	O
has	O
no	O
effect	O
on	O
sensor	O
accuracy	O
and	O
strict	O
voltage	O
regulation	O
is	O
not	O
typically	O
necessary	O
.	O
</s>
<s>
Although	O
the	O
RVDT	B-Algorithm
can	O
theoretically	O
operate	O
between	O
±45°	O
,	O
accuracy	O
decreases	O
quickly	O
after	O
±35°	O
.	O
</s>
<s>
An	O
RVDT	B-Algorithm
can	O
also	O
be	O
designed	O
with	O
two	O
laminations	O
,	O
one	O
containing	O
the	O
primary	O
and	O
the	O
other	O
,	O
the	O
secondaries	O
.	O
</s>
<s>
A	O
similar	O
transformer	B-Algorithm
is	O
called	O
the	O
Rotary	O
Variable	O
Transformer	B-Algorithm
and	O
contains	O
only	O
one	O
secondary	O
winding	O
giving	O
only	O
one	O
voltage	O
:	O
</s>
