[Amps] Alpha 87A Power Supply Question

[Adrian]

It is dangerous, additional to my earlier post connecting neutral to 
chassis and wiring 120v returns to same terminal, if the neutral 
connection opens anywhere from within the amp back to the supply, then 
you have 120v on the amp chassis at turn on, waiting for you to grab.

Usually, it takes about 30 mA of current to cause respiratory paralysis. 
Currents greater than 75 mA cause ventricular fibrillation (very rapid, 
ineffective heartbeat).


vk4tux




On 6/5/21 5:03 pm, gudguyham via Amps wrote:
Some of the old Henry amps actually require a neutral to be present when 
using the amp on 240v.  On 120v it makes no difference because if you 
have two wires, hot and neutral (120v) the neutral is available.  When 
switching to 240vac if you lack the neutral, they instruct you to use 
ground to carry the fan, and low voltage transformer neutrals.  This 
practice is NOT good and could be dangerous.  The neutral that is 
required is hooked up to a separate terminal at the rear of the amp, 
this is the neutral being sought out by the fan and LV transformer.  The 
simple fix which satisfies all conditions is to NOT use ground( the 
green wire) to this terminal as a neutral, but rather use a jumper wire 
at the two terminals that series up the dual primary to that terminal. 
  By doing this there is no need for an external neutral and the green 
wire can be used as chassis ground as intended.