From H alpha radial velocities taken in quiescence we find orbital periods
of 0.1591 +/- 0.0004 days, or 3.82 hr, for CY Lyr, 0.207584 +/- 0.000007 da
ys, or 4.98 hr, for TW Tri, and 0.16870 +/- 0.00007 days, or 4.05 hr, for V
W Vul. The period of VW Vul is much longer than a previously published valu
e, and the spectrum suggests that we caught this Z Cam star in standstill.
The revision of VW Vul's period resolves its problematic status as a short-
period dwarf nova that did not show superoutbursts. The quiescent spectra o
f CY Lyr and TW Tri are typical of dwarf novae between outbursts, and both
show the contribution of a late-type secondary, of type similar to M3.5 in
CY Lyr and similar to M1 in TW Tri. From the M-dwarf contribution in the qu
iescent spectrum we estimate distances of similar to 330 pc for CY Lyr and
similar to 800 pc for TW Tri. On 1997 June 30 UT we observed CY Lyr in a ri
se to outburst, and we present spectra obtained approximately hourly as the
object brightened.