Time value of field is not valid

I have written a field as follows:

time_of_measurement = fields.Time('Time At Measurement(hr/hrs)', format="%H")

But when I try to save the form in which this field is written, this error shows up:

The time value “01:42:05” of field “Time At Measurement(hr/hrs)” on “model_name” is not valid.

Any help is appreciated

With the format that you specified, you can only enter rounded hours like 01:00, 2:00 but not time with minutes or seconds.