I have read about how to do this and most come up with this solution. I just want to display the time format.
$starttime = \"1899-12-30 06:52:47\";
As mentioned in the comments your date is before the unix epoch. DateTime() allows you to work around that.
$dt = new DateTime("1899-12-30 06:52:47");
echo $dt->format("h:i:s");
$starttime = "1899-12-30 06:52:47";
echo date("h:i:s",strtotime($starttime));
This code works ok for me and displays "06:52:47". It could possibly be because 1899 is before the Unix Epoch (00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970)