title: Trying to use NSDate for time only
body: <p>I'm struggling to find a way to use NSDate for time only purposes.
  I was trying to do the following code:</p>
  
  <pre><code>- (void)awakeFromInsert
  {
      NSDateComponents *comps = [[NSDateComponents alloc] init];
      comps.minute = 45;
      comps.second = 0;
  
      NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
      self.periodDuration = [calendar dateFromComponents:comps];
      NSLog(@"periodDuration: %@",self.periodDuration);
  
      comps = [[NSDateComponents alloc] init];
      comps.hour = 8;
      comps.minute = 0;
      self.firstPeriodStartTime = [calendar dateFromComponents:comps];
      NSLog(@"firstPeriodTime: %@",self.periodDuration);
  }
  </code></pre>
  
  <p>But the result I get is:</p>
  
  <pre><code>periodDuration: 0001-12-31 22:24:04 +0000
  firstPeriodTime: 0001-12-31 22:24:04 +0000
  </code></pre>
  
  <p>The result I was expecting:</p>
  
  <pre><code>periodDuration: 45:00
  firstPeriodTime: 08:00
  </code></pre>
  
  <p>What am I doing wrong? How can I fix this?
  Thank you.</p>