I thought a lot and now i have a solution with a foreach loop.
The Code looks like this:
<div class="carousel-inner" role="listbox">
<?php
$i=0;
$posts = get_posts('numberposts=3');
foreach ($posts as $post ) :setup_postdata( $post);
?>
<div class="item <?php if($i==0) echo 'active';?>">
<?php if (has_post_thumbnail()){
$thumbnail = wp_get_attachment_image_src( get_post_thumbnail_id(), 'full');
?>
<img src="<?=$thumbnail[0];?>" alt="First slide">
<?php } ?>
<div class="container">
<div class="carousel-caption">
<h1><?php the_title();?></h1>
<p><?php the_excerpt();?></p>
<p><a class="btn btn-lg btn-primary" href="<?php the_permalink();?>" role="button">Weiterlesen...</a></p>
</div>
</div>
</div>
<?php
$i++;
endforeach;
wp_reset_postdata();
?>
</div>
The topic can be closed ??