Whirlpool MAH3000 service manual Torque Output, Vcc REFERENCE VOLTAGE OUTPUT, Water Valve Outputs

The machine control counts the number of rinses during a normal wash cycle. In the first and second Rinse Tumble increments, the machine control will energize the Timer Mo- tor Output as soon as the Pressure Switch In- put is no longer energized, indicating that the water has reached the full level. In the third and fourth (if Extra Rinse is selected) Rinse Tumble increments, the machine control will energize the Timer Motor Output 30 seconds after the Pressure Switch Input is no longer asserted.

The machine control will energize the Timer Motor Output when the timer is set into a Spin1, Spin2, or Spin3 increment 30 seconds before the end of the spin. It will remain ener- gized until the timer inputs change.

TORQUE OUTPUT

The machine control commands motor speed and direction through the Torque Output from the machine control to the motor control. This output is a pulse width modulated (PWM) signal (See Section 2: Machine Control).

Vcc REFERENCE VOLTAGE OUTPUT

The Vcc Outputs are a reference voltage for many of the signal outputs. On the machine control, the Vcc outputs are 24 VDC refer- enced to the 120 VAC neutral line.

WATER VALVE OUTPUTS

The machine control determines whether the hot or cold Water Valve Outputs should be en- ergized during each timer increment, but it only gates the power to the water valves, it does not directly provide that power. When the timer is in an increment calling for water, power passes from the timer to the wash or rinse level circuit in the pressure switch. When the water level is below the full level, the pres- sure switch circuit is closed and the power passes to the machine control. The machine control gates the power to the hot and cold Water Valve Outputs. When the pressure switch senses that the full level is reached, the

circuit opens and de-energizes the Pressure Switch Input on the machine control, which de-energizes the Water Valve Outputs.

The machine control will read the Water Tem- perature Sensor Input to determine the blended water temperature passing through the water valve. In a warm wash fill, the ma- chine control will first energize both the hot and cold Water Valve Outputs for five seconds then de-energize the cold Water Valve Output and monitor the water temperature. When the Water Temperature Sensor Input passes the warm threshold (approx. 20 K Ohms), the machine control will re-energize the cold out- put for the remainder of the fill.

In a cold wash fill, the machine control will first energize only the cold Water Valve Out- put for five seconds. It then energizes the hot Water Valve Output and monitors the Water Temperature Sensor Input until it passes the cold threshold (approx. 44 K Ohms), when it de-energizes the Hot Water Valve Output for the remainder of the fill.

If the user selects a warm rinse temperature, the machine control will count the rinses and allow a warm rinse fill only on the third and fourth (if the user also selects the Extra Rinse option) rinses. The first two rinses will be cold only. The machine control does not regulate water temperature during the rinses.

NOTE: If the user chooses the Easy Care/ Perm Press fabric selection, all rinse fills will be cold regardless of whether the user also selected the warm rinse temperature.

16008373-01	SECTION 1. GENERAL INFORMATION	1-9
	© 1998 Maytag Corporation