My 1 TB internal hard drive has become too full to use. I have purchased a 5 TB external drive 3.0 USB that will work with 3.0 USB system on my Dell. Has anyone had experience using an external hard drive to store working files for their animation? Is it too slow or are their hang up problems? etc.
-->> My 1 TB internal hard drive has become too full to use.
That sounds very singular. For editing you can't have only one disk. Well, you can but everything is so incredibly slow, even slower than molasses in winter, that you can not effectively finish any project before old age hits you. You need as absolute minimum two disks, but better three.
USB3 connected drives are generally too slow for editing, especially if they are HDD, with one major exception: Samsung T1 USB3 SSD's (up to 1 TB) can be used for editing, even though they are clearly slower than internal SSD's connected over SATA 6G.
If your internal HDD is getting full, add another disk for internal use or even two, best are Samsung 850 Pro SSD's that are available in capacities up to 2 TB.