v19.06 1

600 mm/sec acceleration on x and y, and 100 on z.

v19.06 2

10/9/19 - reducing acceleration to 1000 on X and y
10/8/19 - 3000 mm/sec acceleration on x and y, and 100 on z. Too much vibration.

Voltage on stepper driver - E, x, y - 0.5V; z is 1.05V
Without power, heat bed was at 120V, and I got a shock even though the bed is on the GFCI! Did I hit the rare condition where a shock is possible? I touched the top plate of the heat bed and the frame of the printer, both of which are isolated from each other. What is happening? And does a ground on the frame and on the heat bed fix this? THis calls for some experiments to verify correct behavior. For example, if there is a short in the bed, the GFCI should trip via overcurrent, or upstream breaker should trip if on the grid. Test 1: short on GFCI ('fork' into both sides of the gfci): breaker in power strip tripped immediately.
Fixed a short in heat element. After that, Bed plate metal with reference to metal frame is 16V. Is that inductive voltage from the AC in the bed? Voltage from bottom output terminal of SSR with reference to frame is 75V. Voltage from top output terminal is 16V.