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--- astra_conv:conversion:cooling_system:cooling_system [2014/03/20 17:29]
richard
+++ astra_conv:conversion:cooling_system:cooling_system [2014/05/03 19:57] (current)
richard
@@ Line 3: / Line 3: @@
 ====== cooling system  ======
-As mentioned before, the motor is foreseen for watercooling, but this is not required in any case. Watercooling is however a safety measure to prevent that the controller throttles down the motor at persistently high load, especially in hot weather.
+As mentioned before, the motor is fitted for liquid cooling. Although it can even be operated "dry", cooling  prevents that the controller throttles down the motor at persistently high load, especially in hot weather.
-Besides the coolant ducts of the motor itself, the water cooling circuit consists of a small cooler from a Honda 250 scooter and a circulation pump. Together with the heater circuit (which has its own circulation pump), the cooling circuit is connected to the original coolant liquid reservoir. The air buffer in the reservoir can be pressurized to ease refilling and emptying of the two circuits.
+In contrast to the motor, the controller is air cooled. It also tends to overheat under harsh conditions, so the cooling system includes forced air cooling of the controller. The cooler fan of the air conditioning system is reused for this purpose.
-The cooler got a place near the front grille, at the passenger side. From it's scooter past, it already has a small fan attached.
-{{:astra_conv:conversion:motor_cooler:p1110310.jpg?770|}}
-DIY bleeder screw at the top of the cooler:
-{{:astra_conv:conversion:motor_cooler:p1110255.jpg?340|}} {{:astra_conv:conversion:motor_cooler:p1110256.jpg?340|}}
-In addition to cooling the motor, I have also employed the cooler fan of the air condition system, for forced cooling of the motor controller.
 The fans and the coolant pump are independently controlled, depending on the temperature of motor respectively motor controller.
-Currently, the components of the cooling system are prepared, but not yet installed.
@@ Line 64: / Line 52: @@
 {{:astra_conv:conversion:motor_cooler:p1110277.jpg?500|}}
+Temperature sensors - The double sensor is glued to the motor. One of the NTCs is for the cooler controller itself.
+The NTC sensor for the motor controller is fitted into a cable shoe and bolted to the motor controller's heat sink.
+The output of the second NTC on the motor is relayed to the temperature gauge in the dashboard (as long as the coolant heater is off). I later added a second NTC mounted on the controller heat sink and connected in parallel to this one, so the temperature gauge actually gives an (exaggerated) "combined" temperature of both motor and controller.
+{{:astra_conv:conversion:motor_cooler:p1110717.jpg?340|}} {{:astra_conv:conversion:motor_cooler:p1110879.jpg?340|}}
 \\
 === function ===
-At 50°C, each fan will start at low speed (around 30% pulse width ratio). Up to 60°C, the pulse width ramps up linearly, and stays at 100% above 60°C. The coolant circulation pump will also be switched on at 50°C.
+At 50°C, the motor cooler fan will start at low speed (around 30% pulse width ratio). Up to 60°C, the pulse width ramps up linearly, and stays at 100% above 60°C. The coolant circulation pump will also be switched on at 50°C.
+The motor controller cooler got a dedicated "sharper" charateristics - it now starts at 45°C heat sink temperature, and reaches 100% duty cycle at 50°C already.
 When ignition is switched on, the pump and the fans will be switched on for a few seconds, for test purposes and to avoid that they seize due to long inactivity.
@@ Line 101: / Line 105: @@
 {{:astra_conv:conversion:motor_cooler:lowest.jpg?225|}}{{:astra_conv:conversion:motor_cooler:low.jpg?225|}}{{:astra_conv:conversion:motor_cooler:highest.jpg?225|}}
-It turned out that both fans can be controlled well via PWM signal. However, both emit quite some audible noise at pulsed operation.
+It turned out that both fans can be controlled well via PWM signal. However, both do emit quite some audible noise at pulsed operation.
+\\
+===== liquid coolant circuit =====
+The coolant liquid is circulated by an electric pump, through the motor and though a small radiator. Together with the heater circuit (which runs independently and has its own circulation pump), the cooling circuit is connected to the original coolant liquid reservoir. The air buffer in the reservoir will take up thermal expansion of the coolant liquid, and it can be pressurized to ease refilling and emptying of the two circuits.
+Overview of the cooling system's components, ready for installing:
+{{:astra_conv:conversion:motor_cooler:p1110736.jpg?800|}}
+The cooler got a place near the front grille, at the passenger side. From it's scooter past, it already has a small fan attached.
+{{:astra_conv:conversion:motor_cooler:p1110310.jpg?770|}}
+{{:astra_conv:conversion:motor_cooler:p1110885.jpg?770|}}
+DIY bleeder screw at the top of the cooler:
+{{:astra_conv:conversion:motor_cooler:p1110255.jpg?340|}} {{:astra_conv:conversion:motor_cooler:p1110256.jpg?340|}}
+Coolant terminals on the motor. Please note that the fittings used in below foto turned out not to be tight - I have replaced them later. The new fittings have a flange to press a rubber gasket against the motor's case.
+{{:astra_conv:conversion:drivetrain:P1100856.jpg?600|}}
+The coolant pump (again a Volkswagen Vanagon Turbo Diesel circulation pump, as for the heater circuit). This recent model by the way has a brushless motor with magnetic coupling to the pump chamber. It runs on very low current and appears quite long-lasting.
+{{:astra_conv:conversion:motor_cooler:p1110884.jpg?600|}}
+As usual, every component has its own flange diameter, and I needed to solder a couple of adapters. To start with, it is always good to have a plan of the puzzle:
+{{:astra_conv:conversion:motor_cooler:p1110719.jpg?600|}}
+The first picture shows two mistaken ones, corrected in the second picture. Note the additional small diameter pipe on one of the adapters. It connects the cooling circuit to the coolant reservoir via a thin hose.
+{{:astra_conv:conversion:motor_cooler:p1110734.jpg?340|}} {{:astra_conv:conversion:motor_cooler:p1110880.jpg?340|}}
+Testing cooler and fittings for tightness:
+{{:astra_conv:conversion:motor_cooler:p1110732.jpg?600|}}

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